PETERS, C.J.

These consolidated criminal appeals from the imposition of the death penalty upon the defendant, Michael B. Ross, raise numerous issues concerning the validity of his capital felony convictions and the validity of the procedures that resulted in death sentences for each of these convictions. After a trial to determine guilt, a jury convicted the defendant of six counts of capital felony in violation of General Statutes 53a-54b. At a separate sentencing hearing pursuant to General Statutes 53a-46a, the same jury considered further evidence and found an aggravating factor and no mitigating factor with respect to each count. As a result, the trial court rendered a judgment imposing the death sentence on the defendant on each count. The defendant has appealed to this court in accordance with General Statutes 51-299 and 53a-46b. We affirm the defendant's conviction of all counts of capital felony. Because of improprieties in the conduct of the sentencing hearing, however, we reverse the judgments imposing the death penalty and remand for new sentencing hearings on all counts.

The jury could reasonably have found the following facts. On June 13, 1984, the defendant accosted seventeen year old Wendy B. as she was walking along Route 12 in Lisbon. After a short conversation, he pulled Wendy B. over a stone wall, forcing her to go with him into a wooded area that led to an open field. There he sexually assaulted her, forced her to turn over on her stomach, and then strangled her.

On Thanksgiving Day, 1983, the defendant accosted nineteen year old Robyn S. on the grounds of Uncas on Thames State Hospital in Norwich. He forcefully pulled Robyn S. into a wooded area and ordered her to remove her clothing. He then sexually assaulted her and, after ordering her to turn over on her stomach, strangled her. Before leaving, he covered her body with leaves.

On Easter Sunday, 1984, the defendant picked up fourteen year old April B. and fourteen year old Leslie S., who were hitchhiking to Jewett City on Route 138. Once the girls had entered his car, he drove them easterly on Route 165 and, over their protests, past their intended destination. When April B. tried to force the defendant to stop the car by threatening him with a knife, he disarmed her and continued to transport the girls against their will, through eastern Connecticut, to Beach Pond in Rhode Island. At Beach Pond, he parked his car and bound both girls hand and foot. He then untied April B.'s feet and forced her to walk a short distance from his car, where he assaulted her sexually, turned her over on her stomach and strangled her. Returning to the car, the defendant killed Leslie S. without sexually assaulting her. He then placed the bodies of both girls in his car and drove back to Preston, Connecticut, where he deposited their bodies in a culvert.

At his trial, the defendant did not deny having committed the sexual assaults, the kidnappings and the murders described above. His defense was insanity, a defense that the jury rejected by finding him guilty as charged. Additional facts will be discussed as they become relevant to the issues before us.

The defendant's appeal raises a multitude of issues, which we will address in three main parts. First, we will consider the validity of the defendant's conviction of six counts of capital felony. Second, we will consider the facial constitutionality, under the federal and state constitutions, of imposing the death penalty upon a person who has been found to have committed, in an especially heinous, cruel or depraved manner; 53a-46a(h)(4); a capital felony under subsection (5) or subsection (7) of 53a-54b. Third, we will consider the validity, pursuant to 53a-46a, of the defendant's sentencing hearing. In light of our remand for a new sentencing hearing because of substantial noncompliance with the statutory requirements of 53a-46a, we need not review the defendant's death sentences pursuant to 53a-46b.

I

VALIDITY OF THE CONVICTIONS

The defendant has raised numerous challenges to the validity of his conviction of six counts of capital felony. On jurisdictional grounds, he maintains that the trial court lacked the authority to try him for the two counts of capital felony involving the two murders committed in Rhode Island. On evidentiary grounds, he maintains that the trial court improperly: (1) denied his motions to suppress his incriminatory statements to the police; and (2) restricted his cross-examination of a police officer. On instructional grounds, he maintains that the trial court improperly charged the jury concerning: (1) the inferences that could be drawn from missing witnesses; (2) the special evidentiary requirements for proof of a capital crime; (3) reasonable doubt; (4) the burden of proving insanity; and (5) the unavailability of a defense of extreme emotional disturbance. In addition, he maintains that the trial court improperly: (1) denied his motion for severance; (2) permitted prejudicial commentary by the prosecuting attorney; and (3) rejected claims of juror prejudice. We agree with the state that none of the defendant's claims of error warrant reversal of his convictions.

Before addressing the multiple claims raised by the defendant, we should take notice of two claims that he does not make. He does not challenge the sufficiency of the evidence to support the jury's verdicts that he was guilty, beyond a reasonable doubt, of each of the counts of capital felony with which he was charged under 53a-54b(5) and (7). He similarly does not challenge the jury's determination that he failed to establish his defense of insanity by a preponderance of the evidence.

A

JURISDICTIONAL ISSUES

The defendant maintains that the trial court lacked territorial jurisdiction to try him for the capital felonies relating to the deaths of April B. and Leslie S. because these two victims were not killed in Connecticut. The state argues that Connecticut's continuing jurisdiction over the defendant's kidnapping of these victims provides authority for Connecticut to prosecute him for the capital felonies arising out of the murders committed in Rhode Island.

When the issue of territorial jurisdiction was initially raised in the trial court by the defendant's motion to dismiss, the trial court, Hendel, J., after a hearing, made the following findings of fact. The victims were kidnapped in Connecticut and killed in Rhode Island. At the time of their abduction, the defendant had the intention to assault the victims sexually and to kill them. The victims had the ability to observe the defendant throughout their abduction and thus would have been able to identify him.

From these facts, the trial court concluded that it lacked jurisdiction over the capital felony counts charging the defendant with double murder; 53a-54b(8); and with the sexual assault and murder of April B.; 53a-54b(7); because the alleged murders and sexual assault had been committed entirely in Rhode Island. The trial court concluded, however, that it had jurisdiction over the capital felony counts charging murder in the course of a kidnapping. General Statutes 53a-54b(5). Without challenging the trial court's underlying findings of fact, the defendant argues that its ruling of law was incorrect. We disagree.

Our starting point is the observation that, as a general matter, the Superior Court has no territorial jurisdiction to adjudicate a charge of murder unless the state proves, beyond a reasonable doubt, that the victim was murdered in Connecticut. General Statutes 51-1a(b); State v. Beverly, 224 Conn. 372, 375-76, 618 A.2d 1335 (1993); State v. Volpe, 113 Conn. 288, 294, 155 A. 223 (1931); A. Spinella, Connecticut Criminal Procedure (1985) 18-19, 3A. This point of departure is consistent with the common law principle that limits the state's interest in vindicating its criminal laws to the reach of its territory. State v. Volpe, supra; State v. Grady, 34 Conn. 118, 129-30 (1867); Gilbert v. Steadman, 1 Root 403 (1792). This principle of limited territorial jurisdiction presumably underlay the trial court's dismissal of the capital felony count charging the defendant with having violated 53a-54b(8).

The issue before us is whether a different rule should apply to a capital felony that is defined by statute as a "murder by a kidnapper of a kidnapped person during the course of the kidnapping or before such person is able to return or be returned to safety." General Statutes 53a-54b(5). The defendant emphasizes that the statute punishes an aggravated form of murder, so that the gravamen of the offense charged is the homicide that occurred in Rhode Island. The state argues, to the contrary, that the statute prescribes a linkage between kidnapping and murder that allows the exercise of territorial jurisdiction over the consequences of a kidnapping that began in Connecticut. The state emphasizes the trial court's finding of fact that, at the time of their abduction, the defendant had the intention to assault the victims sexually and to kill them.

This specific issue is a matter of first impression for this court. To resolve it, we must examine our common law with respect to territorial jurisdiction, as well as changes brought about by the enactment of the penal code.

Prior to the enactment of the penal code, our common law cases reviewed this state's exercise of jurisdiction over a number of continuous crimes that had a significant nexus with another state. In those cases, we held that our courts had jurisdiction to consider charges of larceny brought against criminal defendants who are discovered in this state with property stolen in another state. State v. Keeby, 159 Conn. 201, 206, 268 A.2d 652 (1970), cert. denied, 400 U.S. 1010, 91 S.Ct. 569, 27 L.Ed.2d 623 (1971); State v. Palkimas, 153 Conn. 555, 561-62, 219 A.2d 220 (1966); State v. Pambianchi, 139 Conn. 543, 547, 95 A.2d 695 (1953); State v. Cummings, 33 Conn. 260, 264-65 (1866). Similarly, we held that a defendant had committed the crime of embezzlement in this state when he received bonds in Connecticut, with the present intent to sell them and to appropriate their proceeds, even though the embezzled bonds were actually sold in another state and the proceeds realized there. State v. Serkau, 128 Conn. 153, 156-57, 20 A.2d 725 (1941).

In each of these cases at common law, we construed our statutes to impose criminal liability on the defendants for their conduct in Connecticut. In the larceny cases, we held that our larceny statute imposed criminal liability on the continued retention in Connecticut of stolen property regardless of its provenance. In the embezzlement case, we held that our statute imposed liability on the felonious appropriation of property in Connecticut regardless of the locale of the completion of the defendant's felonious plan. The defendants in those cases were therefore properly convicted in Connecticut, not because Connecticut was exercising extraterritorial jurisdiction, but because the state had established that each element of the crimes charged had been proven to have occurred in this state. See A. Spinella, supra, 18-21. As the defendant correctly points out, the cited precedents would permit a Connecticut prosecution of a capital felony if a murder occurred in this state following a kidnapping that had begun in another state. They would likewise permit a Connecticut prosecution for a kidnapping that began in Connecticut but continued until the victims were released in another state. Presumably they would also encompass a Connecticut prosecution for a murder commenced by a physical attack on a victim in this state, with the intent to kill, even though the victim actually died in a hospital in Rhode Island. See Pollard v. State, 270 Ind. 599, 388 N.E.2d 496 (1979). Those are not, however, the facts of this case.

Adoption of the penal code abrogated our common law of crimes. Valeriano v. Bronson, 209 Conn. 75, 92, 546 A.2d 1380 (1988). Nothing in the text of the penal code indicates that the legislature addressed questions of extraterritorial jurisdiction. The state urges us to adopt the expanded view of extraterritorial jurisdiction advocated by the Model Penal Code, pursuant to which a state has jurisdiction over any crime whenever at least one element of the crime occurred within the state. See 1 A.L.I., Model Penal Code and Commentaries (1985) 1.03. Although our penal code commission apparently noted and discussed an earlier version of the Model Penal Code incorporating the same expanded view of jurisdiction; see 1967 Report of the Commission to Revise the Criminal Statutes p. 42; that discussion did not result in any textual articulation of legislative intent. See A. Spinella, supra, 3A. The defendant urges us to conclude that enactment of our penal code, without a specific adoption of the Model Penal Code as to jurisdiction, limits the jurisdiction of our courts to crimes committed within this state.

The closest that we have come to judicial adoption of the Model Penal Code's view of jurisdiction is State v. Stevens, 224 Conn. 730, 620 A.2d 789 (1993). In that case, we held that a police officer, after a lawful arrest in Connecticut for a crime committed in this state, did not exceed permissible territorial limitations on his jurisdiction by having blood tests performed on an allegedly intoxicated driver at the nearest emergency medical facility in Rhode Island. Id., 742-43. Citing the Model Penal Code, we began our discussion by stating that there are situations in which "even a criminal statute may have extraterritorial effect. See, e.g., Strassheim v. Daily, 221 U.S. 280, 284, 31 S.Ct. 558, 55 L.Ed. 735 (1910) (upholding prosecution in Michigan for acts of bribery and obtaining public money under false pretenses by defendant in Illinois, offenses by their nature peculiarly injurious to the state of Michigan); see also People v. Tyler, 7 Mich. 161, 221 (1859) (`every sovereignty has the right, subject to certain restrictions, to protect itself from, and to punish as crimes, certain acts which are peculiarly injurious to its rights or interests, or those of its citizens, wherever committed'). (Emphasis in original.)" Id., 738.

In State v. Stevens, supra, 224 Conn. 739, we nonetheless resolved the issue in favor of jurisdiction on a narrower ground than that advocated by the Model Penal Code when we invoked a test that "balance[d] the legitimate interests of the adjoining sovereignties." See also State v. Mueller, 44 Wis.2d 387, 392-93, 171 N.W.2d 414 (1969). We noted that the courts of Rhode Island would have had no jurisdiction over the defendant's offenses; State v. Stevens, supra, 737; and that the statutes of Rhode Island permit "`any one' to arrest or to seize evidence after the commission of `any offense.'" Id., 739. On the Connecticut side of the ledger, we emphasized our state's "unambiguous policy aimed at ensuring that our highways are safe from the carnage associated with drunken drivers." Id. Finally, we looked to the language of the governing Connecticut statute, General Statutes 14-227b. We thought it highly significant that "nothing in the language or legislative history of 14-227b [suggests] that the legislature intended that a police officer should endanger the life of an arrestee by contravening the judgment of emergency medical personnel and requiring them to transport the arrestee to a more distant hospital so that the officer may gather evanescent evidence on Connecticut soil." Id., 742.

Stevens is not a controlling precedent because, in that case, we addressed the extraterritorial authority of a Connecticut police officer, rather than the extraterritorial authority of a Connecticut court. Stevens is, nonetheless, significant because, rather than adopting the provisions of the Model Penal Code wholesale, we undertook an examination of the underlying public policy and a close reading of the relevant statutes.

Applying the methodology of Stevens, we note that Stevens assumed that, as a matter of public policy in the realm of criminal law, the General Assembly has the constitutional authority to enact a statute that has an extraterritorial effect. We agree with that assumption. As the Supreme Court of Florida has held, if the legislature so directs, "[a] person who commits a crime partly in one state and partly in another state may be tried in either state under the sixth amendment of the United States Constitution." Lane v. State, 388 So.2d 1022, 1028 (Fla. 1980); see also Conrad v. State, 262 Ind. 446, 450, 317 N.E.2d 789 (1974); State v. Harrington, 128 Vt. 242, 250, 260 A.2d 692 (1969). Connecticut does not lack the authority to make it a capital crime in Connecticut to form the intent here to cause the death of a victim elsewhere and to act in furtherance thereof or to commit an underlying felony in this state that results in a murder elsewhere. Lane v. State, supra, 1028; see also Heath v. Jones, 941 F.2d 1126, 1138 (11th Cir. 1991).

The ultimate question is, therefore, as Stevens suggests, a matter of statutory construction. We must decide whether, in enacting 53a-54b(5), the legislature manifested its intention to give extraterritorial effect to the capital felony it therein defined as a "murder by a kidnapper of a kidnapped person during the course of the kidnapping or before such person is able to return or be returned to safety." We recognize that, unless a contrary interpretation would frustrate an evident legislative intent, criminal statutes are governed by the fundamental principle that such statutes are strictly construed against the state. State v. Russell, 218 Conn. 273, 278, 588 A.2d 1376 (1991); State v. Torres, 206 Conn. 346, 355, 538 A.2d 185 (1988). We are, however, persuaded that the statute, as drafted, unambiguously manifests the legislature's intent to allow a capital felony prosecution of the defendant in the circumstances of this case.

On its face, the statute requires the state to prove a murder by a kidnapper without requiring that the murder have been committed in Connecticut. The strongest argument against such a literal construction of 53a-54b(5) is that its language does not parallel the language of the felony murder statute, General Statutes 53a-54c. The latter statute provides: "A person is guilty of murder when, acting either alone or with one or more persons, he commits . . . kidnapping . . . and, in the course of and in furtherance of such crime or of flight therefrom, he . . . causes the death of a person other than one of the participants. . . ." When the predicate crime is a kidnapping, the felony murder statute encompasses any killing of the victim that occurs during the victim's unlawful detention. See State v. Gomez, 225 Conn. 347, 350-51, 622 A.2d 1014 (1993). Presumably, the felony murder statute would encompass such a murder if it occurred in another state. Although the language of the capital felony statute is slightly different, because it penalizes a "murder by a kidnapper of a kidnapped person during the course of the kidnapping or before such person is able to return or be returned to safety"; General Statutes 53a-54b(5); we are not persuaded that these differences in statutory formulation are sufficient to ascribe an extraterritorial effect to the one statute and not to the other.

An alternate argument contrary to a literal construction of 53a-54b(5) is premised on the proposition that, because commission of a murder is the major premise for any capital felony under 53a-54b, the legislature cannot have intended to have Connecticut assume jurisdiction over a murder committed in another state under any circumstances. This argument is unpersuasive for two reasons. Structurally, although most subsections of 53a-54b require the state to prove the commission of a murder, subsection (6) has no such requirement. See footnote 3. Linguistically, 53a-54b(5), the subsection presently at issue, speaks of "murder by a kidnapper" and does not prioritize between the commission of the two predicate felonies, kidnapping and murder.

To reach the conclusion that 53a-54b(5) applies to the Rhode Island murders in the circumstances of this case, we need not embrace the policy of the Model Penal Code in its entirety for all criminal prosecutions. It bears emphasis that in this case we have a defendant who, in this state, intentionally committed two kidnappings with the contemporaneous intent to cause the death of his victims. With that intent, and during the uninterrupted course of the kidnappings, he killed the victims. Although the murders occurred in Rhode Island, the defendant returned the victims' bodies to Connecticut. This case, therefore, demonstrates an overwhelming factual nexus between the crimes and Connecticut. We are persuaded that the legislature intended the literal language of the statute to apply to a case so closely tied to the public welfare of this state.

In summary, we conclude that the defendant's jurisdictional defense cannot be sustained in the circumstances of this case. The defendant was properly convicted of the two counts of capital felony arising out of his kidnapping of April B. and Leslie S., even though he murdered them in Rhode Island.

B

EVIDENTIARY ISSUES

The defendant next maintains that several allegedly improper evidentiary rulings entitle him to a new trial. He urges us to conclude that the trial court improperly: (1) denied his motions to suppress his incriminatory statements to the police; and (2) restricted his cross-examination of a police officer. We disagree.

1

On June 28, 1984, while at the Lisbon town hall, the defendant made numerous inculpatory statements to the state police. He admitted, orally and in writing, that he had killed Wendy B. and Robyn S., murders that were committed in New London county. He also confessed to killing April B. and Leslie S. in Rhode Island and to other murders in Windham county.

After an evidentiary hearing, the trial court, Hendel, J., denied the defendant's motion to suppress his inculpatory statements. In support of its ruling, the trial court made the following findings of fact. The defendant came to the Lisbon town hall voluntarily. He made his first incriminatory statement to detective Michael Malchik before having received Miranda warnings. This statement resulted from an extended conversation in a town hall conference room. During this conversation, the defendant was not physically restrained and twice had been advised that he was free to leave. It was the defendant who initiated an inquiry into the type of person who might have killed Wendy B. and whether such person might receive psychotherapy. The defendant then asked Malchik whether Malchik thought the defendant had killed Wendy B. Malchik replied in the affirmative and told the defendant that he felt that "he [the defendant] would do it again and I thought that was the most important thing, that he didn't do it again." Immediately thereafter, without any questioning by Malchik, the defendant admitted to having killed Wendy B. Upon hearing this incriminatory statement, Malchik terminated any further conversation with the defendant and treated him as a custodial suspect. Before asking any further questions, Malchik gave the defendant the required Miranda warnings; Miranda v. Arizona, 384 U.S. 436, 86 S.Ct. 1602, 16 L.Ed.2d 694 (1966); and asked the defendant to sign a Miranda waiver, which he did. All the defendant's subsequent incriminatory statements followed repeated Miranda warnings and waivers.

The trial court concluded that: (1) the police had not illegally detained or arrested the defendant; (2) the defendant had made his statements to the police voluntarily; and (3) there was no Miranda violation in the manner in which the police obtained statements from the defendant. Accordingly, the trial court denied the defendant's motion to suppress.

On appeal, the defendant does not challenge the trial court's determination that he came to the Lisbon town hall voluntarily and, while there, made his incriminatory statements voluntarily. His principal claim, rather, is that his noncustodial interview with Malchik was transformed into a custodial detention once Malchik told the defendant that he, Malchik, thought that the defendant had killed Wendy B. Immediately thereafter, according to the defendant, Miranda warnings were required. Because no such warnings were given until after he made his first incriminatory statement, he claims that all his subsequent statements should have been suppressed. We disagree.

To sustain the defendant's argument, we would have to conclude that the trial court made a clearly erroneous finding of fact when it determined that the defendant was not in custody at the time that he told Malchik that he had killed Wendy B. State v. Northrop, 213 Conn. 405, 414, 568 A.2d 439 (1990); State v. Pittman, 209 Conn. 596, 606, 553 A.2d 155 (1989). "A person is in custody only if, in view of all the surrounding circumstances, a reasonable person would have believed he was not free to leave. . . . `Although the circumstances of each case must certainly influence a determination of whether a suspect is "in custody" for purposes of receiving Miranda protection, the ultimate inquiry is simply whether there is a "formal arrest or restraint on freedom of movement" of the degree associated with a formal arrest. . . .'" (Citations omitted.) State v. Pittman, supra, 608. "[A]n officer's [articulated] views concerning the nature of an interrogation, or beliefs concerning the potential culpability of the individual being questioned, may be one among many factors that bear upon the assessment whether that individual was in custody," but such statements are not, of themselves, "dispositive of the custody issue, for some suspects are free to come and go until the police decide to make an arrest." Stansbury v. California, ___ U.S. ___ 114 S.Ct. 1526, 150, 128 L.Ed.2d 293 (1994).

Malchik testified that, just prior to the defendant's first incriminatory statement, Malchik would have allowed the defendant to leave the conference room had he elected to do so, even though Malchik had felt that the defendant had killed Wendy B. The objective circumstances are in accord with this intent. Malchik came and went from the conference room, leaving the defendant alone on several occasions. Immediately before the interchange between the defendant and Malchik, the defendant had been told that he could leave at any time, and he had responded that he understood he was there voluntarily. Also, when concern was expressed that the defendant would be late for work, the defendant had responded that he did not need to leave for work but was willing to stay and talk. We find it especially probative that, contrary to the facts of the cases on which the defendant relies, it was the defendant, not Malchik, who initiated the discussion of the murder of Wendy B. The defendant deliberately solicited Malchik's belief that the defendant had killed Wendy B. Immediately thereafter, although no question had been posed by Malchik, the defendant spontaneously offered that he had killed Wendy B. Considering the record of the meeting in its entirety, we are persuaded that the trial court was not clearly erroneous in its determination that a reasonable person in the defendant's position would have felt free to leave even after Malchik had voiced his belief that the defendant had killed Wendy B.

The defendant also challenges the validity of the Miranda waivers that he executed prior to giving further incriminatory statements. In large part, this argument is predicated upon his contention, which we have rejected, that his first incriminatory statement was inadmissible. The defendant also argues, however, that even if that statement was properly admitted, he was given contradictory directions that undermined his ability to exercise the independent judgment implied in the execution of Miranda waivers. We are convinced, however, that the trial court properly found, in light of all the circumstances, that the defendant had knowingly, intelligently and voluntarily waived his rights. The defendant was both a college graduate and a person with prior experience with the criminal justice system. He adduced no persuasive evidence of police overreaching or coercion.

2

Alternatively, the defendant claims that the trial court's findings at the suppression hearing should be set aside because the trial court improperly: (1) restricted his opportunity to cross-examine Malchik during the suppression hearing; and (2) denied his subsequent motion to open the suppression hearing. Both claims relate to the defendant's efforts to link the reliability of Malchik's testimony concerning the admissibility of the defendant's incriminatory statements to the reliability of Malchik's testimony concerning his investigatory efforts to ascertain the geographical location of the murders that were committed in Rhode Island. We reject both claims.

During the suppression hearing, the defendant attempted to challenge the credibility of Malchik's testimony that the defendant had not been in police custody prior to his first incriminatory statement. The defendant sought, in this regard, to question Malchik about his failure immediately to investigate and locate the scene of the murders that had occurred in Rhode Island. Although the trial court originally sustained an objection by the state on the ground of immateriality, it thereafter reversed its ruling and permitted the defendant to pursue his inquiry. The only question ultimately excluded related to Malchik's failure to ask the defendant to take the police to the place where the crimes had been committed. Because that question did not impugn Malchik's motive, interest, bias or prejudice, the trial court's ruling did not deprive the defendant of his constitutional rights under the sixth amendment to the United States constitution. State v. Vitale, 197 Conn. 396, 402-403, 497 A.2d 956 (1985); State v. Talton, 197 Conn. 280, 284, 497 A.2d 35 (1985). Having afforded the defendant his constitutional rights, the trial court did not abuse its discretion by excluding this one question on the ground that it related to matters immaterial to the suppression hearing. See State v. Dobson, 221 Conn. 128, 137, 602 A.2d 977 (1992).

At a hearing held, a year later, on the defendant's motion to dismiss the counts relating to the Rhode Island murders for lack of territorial jurisdiction, Malchik was again questioned about his failure immediately to ascertain the geographical location of these murders. During the hearing, the trial court expressed its concern that Malchik had not offered a credible explanation for this investigatory delay. As a result of the questions raised at the dismissal hearing, the defendant moved to open the suppression hearing.

In a posttrial articulation, after having reviewed the relevant transcripts, the trial court withdrew its criticism of Malchik's investigation and stated that, in its view, Malchik had testified truthfully during the suppression hearing. In light of the articulation, we conclude that the trial court's denial of the motion to open the suppression hearing was not an abuse of its discretion. The court could reasonably have concluded that Malchik's credibility concerning his investigatory activities subsequent to the defendant's confessions was collateral to his credibility about the events leading up to the confessions. The defendant's offer of proof, in support of his motion to open, consisted solely of the representations of counsel and centered on the defendant's contention that Malchik had taken him into custody as soon as Malchik invited him to drive with Malchik to the town hall, a claim that has now been abandoned.

We have examined the defendant's challenges to the admissibility of his incriminatory statements under the principles established by the United States constitution and Connecticut common law. Although the defendant's brief adverts to independent rights under the Connecticut constitution, no such arguments have been briefed and they are therefore deemed to have been waived. See State v. Hamilton, 228 Conn. 234, 246 n. 10, 636 A.2d 760 (1994). We conclude, therefore, that the trial court properly admitted the defendant's incriminatory statements into evidence.

3

During the trial to adjudicate the defendant's guilt of the crimes with which he had been charged, the defendant renewed his effort to cross-examine Malchik about his investigatory efforts with respect to the Rhode Island murders. Although the defendant characterized this inquiry as relevant to Malchik's credibility, the trial court, Ford, J., could reasonably have concluded, as did the trial court, Hendel, J., at the suppression hearing, that the motive for Malchik's delay in going to the scene of these crimes was collateral and immaterial. Considering the breadth of the defendant's cross-examination of Malchik, we are persuaded that the defendant's constitutional rights were not impaired, and that the trial court's ruling was not an abuse of its discretion.

C

INSTRUCTIONAL ISSUES

The defendant also maintains that he is entitled to a new trial to determine his guilt because the trial court, Ford, J., misinstructed the jury. He claims that the trial court improperly: (1) charged the jury on inferences that might be drawn from his failure to call two witnesses concerning his mental status; (2) failed to charge the jury with respect to the special evidentiary requirements for proof of a capital crime; (3) diluted the charge to the jury on what constitutes proof beyond a reasonable doubt; (4) imposed on the defendant the burden of proving insanity by a preponderance of the evidence and did not fully inform the jury about the consequences of a verdict of not guilty by reason of insanity; and (5) refused to charge the jury on the availability of the defense of extreme emotional disturbance. Because we are unpersuaded that the instructions given by the trial court deprived the defendant of a fair trial, we conclude that reversal of his convictions is not required.

1

The defendant asserts that the trial court improperly gave a Secondino charge instructing the jury that it might draw inferences unfavorable to the defendant because two psychiatric experts whom he had consulted were not called to testify as witnesses on his behalf. In Secondino v. New Haven Gas Co., 147 Conn. 672, 675, 165 A.2d 598 (1960), this court held that "[t]he failure of a party to produce a witness who is within his power to produce and who would naturally have been produced by him, permits the inference that the evidence of the witness would be unfavorable to the party's cause." (Internal quotation marks omitted.) The Secondino rule applies to criminal prosecutions. State v. Grant, 221 Conn. 93, 105, 602 A.2d 581 (1992); State v. Watley, 195 Conn. 485, 488, 488 A.2d 1245 (1985). Although the defendant does not deny that the state has established the procedural prerequisites for a Secondino charge, he maintains that a Secondino charge is fundamentally inconsistent with his privilege to consult psychiatric experts in furtherance of his insanity defense. In the circumstances of this case, he maintains, therefore, that the Secondino charge was both improper and harmful. Although we recognize the seriousness of the defendant's claim of privilege, we are persuaded that the Secondino charge was not sufficiently prejudicial to warrant reversal of the defendant's convictions.

In State v. Toste, 178 Conn. 626, 628, 424 A.2d 293 (1979), we joined the majority of jurisdictions in holding that "[w]here a psychiatric expert, whether psychiatrist or psychologist, is retained by a criminal defendant or by his counsel for the sole purpose of aiding the accused and his counsel in the preparation of his defense, the attorney-client privilege bars the state from calling the expert as a witness." The defendant urges us to extend this holding to preclude a jury instruction permitting an adverse inference to be drawn from the defendant's failure to call such a psychiatric expert as a witness at trial. The state urges us to hold, to the contrary, that when the other prerequisites for a Secondino charge have been satisfied, the existence of an attorney-client privilege does not bar an instruction permitting the jury to draw whatever inference it deems proper from the absence of an expert psychiatric witness.

Although we have never squarely addressed the overall relationship between a missing witness instruction and an evidentiary privilege, we have in fact applied the Secondino rule in a number of contexts despite the possible existence of a privilege restricting the applicability of the rule. In the very case in which we articulated the missing witness rule, Secondino v. New Haven Gas Co., supra, 147 Conn. 676, we held that the trial court had improperly refused to give a missing witness instruction when the plaintiff, in a personal injury action, had failed to call her treating physician as a witness. In State v. McLaughlin, 126 Conn. 257, 261, 10 A.2d 758 (1939), we held that it was proper for the prosecutor to comment on the failure of the defendant's spouse to testify. More recently, in D'Amico v. Manson, 193 Conn. 144, 153, 476 A.2d 543 (1984), we indicated that the Secondino rule in a habeas corpus proceeding might, in the proper circumstances, permit an adverse inference to be drawn from the defendant's failure to call his trial attorney.

These holdings are not dispositive, however, because they contain no explicit consideration of the relationship between a missing witness instruction and the attorney client-privilege. This question is therefore an issue of first impression for this court. Courts in other jurisdictions are divided. Compare State v. Holsinger, 124 Ariz. 18, 601 P.2d 1054 (1979) (privilege bars adverse inference); O'Connor v. Detroit, 160 Mich. 193, 125 N.W. 277 (1910) (adverse inference permitted); Daniels v. Beeson, 312 So.2d 441 (Miss. 1975) (spousal privilege bars adverse inference); George v. State, 98 Nev. 196, 644 P.2d 510 (1982) (adverse comment on any claim of privilege barred per statute); with Epperson v. State, 650 S.W.2d 110 (Tex.App. 1983) (adverse inference permitted); see also Annot. 26 A.L.R. 4th 9 (1983); Annot., 34 A.L.R.3d 775 (1970); Annot., 32 A.L.R.3d 906 (1970); Annot., 116 A.L.R. 1170 (1938), for extensive documentation of conflicting authorities.

The proper resolution of the defendant's claim of privilege requires a balancing of significant competing interests. These interests include the defendant's need for access to expert psychiatric advice to enable him to establish his insanity defense, the state's need for information to enable it to respond to an insanity defense, and the jury's need to consider all relevant, probative and reliable evidence to enable it to exercise its truth finding function.

It cannot be gainsaid that expert psychiatric advice is critical to a lawyer planning an insanity defense. "[T]he assistance of a psychiatrist may well be crucial to the defendant's ability to marshall his defense. In this role, psychiatrists gather facts, through professional examination, interviews, and elsewhere, that they will share with the judge or jury; they analyze the information gathered and from it draw plausible conclusions about the defendant's mental condition, and about the effects of any disorder on behavior; and they offer opinions about how the defendant's mental condition might have affected his behavior at the time in question. They know the probative questions to ask of the opposing party's psychiatrists and how to interpret their answers." Ake v. Oklahoma, 470 U.S. 68, 80, 105 S.Ct. 1087, 84 L.Ed.2d 53 (1985).

We have, however, repeatedly recognized that the state must be afforded a fair opportunity "to acquire information that will enable it to respond intelligently to defenses that concern a defendant's mental status." (Internal quotation marks omitted.) State v. Manfredi, 213 Conn. 500, 515, 569 A.2d 506, cert. denied, 498 U.S. 818, 111 S.Ct. 62, 112 L.Ed.2d 37 (1990). A defendant waives many significant rights when he chooses to assert a defense of insanity. See, e.g., State v. Jarrett, 218 Conn. 766, 776-78, 591 A.2d 1225 (1991); State v. Steiger, 218 Conn. 349, 362-66, 590 A.2d 408 (1991); State v. Manfredi, supra, 513; State v. Fair, 197 Conn. 106, 109, 496 A.2d 461 (1985), cert. denied, 475 U.S. 1096, 106 S.Ct. 1494, 89 L.Ed.2d 895 (1986); see also Buchanan v. Kentucky, 483 U.S. 402, 421-24, 107 S.Ct. 2906, 97 L.Ed.2d 336, reh. denied, 483 U.S. 1044, 108 S.Ct. 19, 97 L.Ed.2d 807 (1987). Specifically, a defendant's assertion of an insanity defense requires at least a partial waiver of his attorney-client privilege because, under Practice Book 759 and 760, he must disclose defense psychiatric reports and submit to a court-ordered psychiatric examination on behalf of the state.

Furthermore, the Secondino charge serves important evidentiary interests. In contradistinction to an invocation of privilege, "the Secondino inference derives from the maxim that all evidence is to be weighed according to the proof which it was in the power of one side to have produced, and in the power of the other side to have contradicted." (Internal quotation marks omitted.) State v. Shashaty, 205 Conn. 39, 44, 529 A.2d 1308 (1987), cert. denied, 484 U.S. 1027, 108 S.Ct. 753, 98 L.Ed.2d 766 (1988). Permitting consideration of all relevant evidence that bears a reasonable assurance of reliability advances the truth finding function of the jury. See State v. Borrelli, 227 Conn. 153, 159, 629 A.2d 1105 (1993).

The particular facts of this case make it unnecessary for us to strike the definitive balance between these interests today, for even if the missing witness instruction was improper, it was, at best, harmless. Because the instruction relates to a claim arising under state law and does not involve any constitutional right, the defendant bears the burden of proving harmful error if the instruction were deemed to be improper. See State v. Silva, 201 Conn. 244, 250, 513 A.2d 1202 (1986); State v. Conroy, 194 Conn. 623, 627, 484 A.2d 448 (1984). "In order to meet his burden of proving that [an] unwarranted Secondino charge constituted harmful error, the defendant must show that the charge was likely to have affected the verdict. State v. Brown, 187 Conn. 602, 611, 447 A.2d 734 (1982); State v. McClain, 171 Conn. 293, 300, 370 A.2d 928 (1976)." State v. Shashaty, supra, 205 Conn. 44. We evaluate the harmfulness of a nonconstitutional error on the record as a whole. State v. Brown, 187 Conn. 602, 611, 447 A.2d 734 (1982); State v. Tropiano, 158 Conn. 412, 427, 262 A.2d 147 (1969), cert. denied, 398 U.S. 949, 90 S.Ct. 1866, 26 L.Ed.2d 288 (1970). An improper instruction is not automatically harmful merely because it adversely affects a defense. State v. Cooper, 182 Conn. 207, 212-14, 438 A.2d 418 (1980); State v. Ruth, 181 Conn. 187, 196-200, 435 A.2d 3 (1980). We are persuaded that the defendant has not met his burden.

Direct and substantive evidence concerning the missing witnesses was presented to the jury during the course of the defendant's trial. The state's cross-examination of the defense psychiatric experts elicited from them the information that the defendant had also consulted with Bruce Freedman, a clinical psychologist, and Howard Zonana, a psychiatrist. With regard to Freedman, Walter Borden, a psychiatrist who testified on the defendant's behalf, told the jury that he had referred the defendant to Freedman for a quick screening involving numerous psychological tests. Borden acknowledged that Freedman's diagnosis was that the defendant suffered from "intermittent explosive disorder," and that this diagnosis did not comport with his own diagnosis or that of John Cegalis, a clinical psychologist, who also testified on behalf of the defendant. As Borden told the jury, Freedman did not find that the defendant suffered from psychotic thinking or a loss of contact with reality, and further found that the defendant knew what he was doing when he killed the women. With regard to Zonana, Borden testified that he knew the defendant had seen Zonana, that those interviews had been taped, and that they had taken place after Borden had first seen the defendant. Cegalis testified that he knew Zonana and that, although he had not reviewed Zonana's taped interviews of the defendant, he had talked briefly with Zonana subsequent to Cegalis' first interview with the defendant. The involvement of Freedman and Zonana in the defendant's diagnosis, and their absence from the witness stand, was therefore evident to the jury.

The testimony concerning Freedman and Zonana is significant in two respects. First, it reveals that the adverse inference instruction did not weave evidence favorable to the state out of whole cloth, but instead merely highlighted information that had previously been brought out directly, particularly with regard to Freedman. Second, the testimony reveals that the missing witnesses were not insignificant. See Dent v. United States, 404 A.2d 165, 172 (D.C.App. 1979) (repeated references to persons whose absence was not significant more likely to cumulate prejudice to point of distortion).

Furthermore, the psychiatric testimony presented by the defendant's experts cut two ways. While Borden testified that he believed the defendant to have been legally insane at the moment that he killed, and Cegalis testified that he was mentally ill and out of control at that time, both also gave testimony that supported a contrary conclusion. In essence, their testimony was that the defendant's kidnap/rape/murders were ritualistic in nature, and that once the ritual of killing had begun, the defendant could not control himself. Borden initially testified that the killing ritual began when the defendant saw his victim, and later testified that it began when the defendant removed his glasses. When pressed on cross-examination, however, Borden testified that the defendant's urge to kill became uncontrollable only after the defendant had completed the rape, but he could not pinpoint whether it occurred before or after the defendant actually began to strangle his victim. Borden also testified that the defendant was fully aware of all his actions and that he was not psychotic, while Cegalis testified that he could not conclude that the defendant was psychotic.

Although Borden and Cegalis relied on the similarity among all the murders to support their conclusions that the killings were "ritualistic," the evidence presented was inconsistent. Borden testified to at least four incidents when the defendant did not complete the kidnap/rape/murder ritual after his assault had begun, and testified also that the defendant commonly stalked women without ever initiating an assault. Borden also agreed, on cross-examination, that his theory of sexual sadism was inconsistent with the defendant's killing to avoid detection. The jury had substantial evidence before it, including the defendant's confession, that would support a conclusion that the defendant had killed to avoid detection.

Finally, we note that the defendant bore the burden of proof on the issue of insanity. State v. Joyner, 225 Conn. 450, 464-65, 472, 625 A.2d 791 (1993). Consequently, there was no risk that the missing witness inference might have led the jury to distort the proper allocation of the burden of proof, as might have been the case had the state borne the burden. See State v. Brewer, 505 A.2d 774, 777 (Me. 1985); State v. Schneider, 402 N.W.2d 779, 788 (Minn. 1987); State v. Peterson, 266 Minn. 77, 84, 123 N.W.2d 177 (1963).

We reiterate that we do not dismiss lightly the defendant's claim that a Secondino charge was inconsistent with his statutory psychiatric privilege and consequently with that part of his attorney-client privilege relating to his unfettered ability to present an insanity defense. Considering all the evidence that was presented to the jury, we nonetheless conclude that, even if the missing witness instruction should not have been given, it was harmless.

2

The defendant requested the trial court to instruct the jury, in accordance with the terms of General Statutes 54-83, that "[n]o person may be convicted of any crime punishable by death without the testimony of at least two witnesses, or that which is equivalent thereto." The trial court instead instructed the jury that, in order to convict the defendant, it would have to find that there was "material and substantial evidence apart from the statement of the accused that the particular crimes charged were committed by the accused." The jury was told that it had to determine that such evidence "substantially corroborate[d] the admissions or the confessions of the accused." The defendant maintains that these instructions so deviated from the requirements of 54-83 that he is entitled to a new trial. We disagree.

First enacted in 1672, 54-83 has been construed, in this century, to have a dual function. The statute not only imposes an additional evidentiary burden on the state but requires the finder of fact, upon proper instructions, to determine whether the state has met its burden. The defendant therefore has a statutory entitlement to an instruction informing the jury that, in capital cases, the state has an additional evidentiary burden above and beyond its obligation to prove its case beyond a reasonable doubt. See State v. Cots, 126 Conn. 48, 58, 9 A.2d 138 (1939); State v. Williams, 90 Conn. 126, 129, 96 A. 370 (1916); State v. Marx, 78 Conn. 18, 22, 60 A. 690 (1905).

The evidentiary burden imposed on the state by 54-83 does not, however, preclude a finding of guilt in capital cases in which the state cannot produce two eyewitnesses to the crime. Because the statute allows the state to have recourse to "equivalent" evidence, the state can satisfy its statutory burden by producing more than one witness to provide circumstantial evidence from which the jury may infer the defendant's guilt. State v. Malm, 142 Conn. 113, 118-19, 111 A.2d 685 (1955); State v. Taborsky, 139 Conn. 475, 483-85, 95 A.2d 59 (1953); State v. Cots, supra, 126 Conn. 57; State v. Chin Lung, 106 Conn. 701, 705, 139 A. 91 (1927); State v. Schutte, 97 Conn. 462, 468-69, 117 A. 508 (1922).

The defendant in this case accordingly does not claim that the state adduced insufficient evidence to prove his guilt beyond a reasonable doubt. With respect to all his victims, the defendant's confessions were corroborated by the presence of the girls' bodies and clothing at the locations to which the defendant led the police. In addition, medical testimony confirmed that all but one of the victims had been sexually assaulted and that all had been strangled.

The defendant maintains, nonetheless, that, in light of his request for an instruction pursuant to 54-83, the trial court improperly failed to inform the jury of the state's additional evidentiary burden under the statute. We agree that the trial court should have instructed the jury expressly in accordance with the language of the statute. In explaining the applicability of the statute to the circumstances of this trial, the trial court would, appropriately, however, have gone beyond the statutory language. State v. Gabriel, 192 Conn. 405, 419, 473 A.2d 300 (1984). An appropriate explanation of the statute would have presented to the jury substantially those instructions that the trial court actually gave. The trial court's description of the evidentiary burden imposed by the statute closely paralleled the instructions concerning 54-83 that we approved in State v. Taborsky, supra, 139 Conn. 484-85.

Even when a defendant requests an instruction that is legally correct, "a court need not tailor its charge to the precise letter of such a request. . . . If a requested charge is in substance given, the court's failure to give a charge in exact conformance with the words of the request will not constitute a ground for reversal. . . . . Whether a charge is possibly misleading depends on the substance rather than the form of what is said." (Citations omitted; internal quotation marks omitted.) State v. Ortiz, 217 Conn. 648, 662, 588 A.2d 127 (1991). Deviation from a requested instruction is, at most, harmless error so long as the trial court's instructions include the material portions of the defendant's request and provide the jury with "a clear understanding of the issues presented for [its] consideration, under the offenses charged and upon the evidence . . . ." State v. Harden, 175 Conn. 315, 322-23, 398 A.2d 1169 (1978); State v. Harrell, 199 Conn. 255, 269-71, 506 A.2d 1041 (1986). We are persuaded that, in the circumstances of this case, the defendant was not harmed by the form in which the trial court responded to his request for an instruction pursuant to 54-83.

3

During its instructions on reasonable doubt, the trial court told the jury that "[p]roof beyond a reasonable doubt can probably best be described as that proof which leaves you with a strong and abiding conviction that the accused is guilty of the crimes with which he has been charged." Although no exception was taken to this charge at trial, the defendant urges us to conclude that the language employed by the court so diluted the standard of proof beyond a reasonable doubt that the defendant was deprived of his fundamental constitutional right to due process. We disagree. "This court has previously reviewed similar language in jury charges on reasonable doubt and has consistently rejected the proposition that such language amounts to a constitutional error." State v. Adams, 225 Conn. 270, 291, 623 A.2d 42 (1993); see also State v. Kelley, 229 Conn. 557, 567-68, 643 A.2d 854 (1994).

4

The trial court instructed the jury, in accordance with the provisions of General Statutes 53a-12 and 53a-13, that the defendant bore the burden of proving his affirmative defense of mental disease or defect by a preponderance of the evidence. The defendant argues that the statutes imposing this burden of proof upon him violate the due process clause contained in article first, 8 and 9, of the Connecticut constitution. We disagree. The defendant's argument principally relies on contentions that we have expressly considered and rejected in State v. Joyner, supra, 225 Conn. 465, 472. We are unpersuaded by his further suggestion that a capital felony prosecution inherently requires a higher standard of due process than would be appropriate for any other serious criminal prosecution.

Also in connection with the defense of mental disease or defect, the trial court instructed the jury, in accordance with the provisions of General Statutes 54-89a, concerning the consequences of a verdict of not guilty by reason of insanity. The defendant had expressly exercised his right to refuse to waive the requirement that the jury be told the consequences of such a verdict. The court, however, denied the defendant's request to inform the jury, in its instructions, that he previously had been convicted of capital felonies in Windham and, in those cases, had already been sentenced to two life terms of imprisonment totaling 120 years. The court's refusal of the defendant's request to charge was justified by our holding in State v. Wood, 208 Conn. 125, 144, 545 A.2d 1026, cert. denied, 488 U.S. 895, 109 S.Ct. 235, 102 L.Ed.2d 225 (1988), that 54-89a should be strictly construed. The statute mandates only that the jury learn the consequences of the matters directly before it, to enable it "to reach a determination based on the evidence . . . unaffected by sympathy, fear or other inappropriate and irrelevant concerns." Id. The trial court was, therefore, not required to inform the jury concerning the consequences of the defendant's prior convictions.

5

The trial court further instructed the jury, in accordance with the defendant's request, that it could consider whether the defendant's culpability for capital felony should be reduced because of evidence that he suffered from an extreme emotional disturbance. See General Statutes 53a-54a(a) and 53a-55(a)(2). In its original instructions, the court informed the jury that it was to consider this defense only if it had rejected guilt on the capital felony offenses and was considering the defendant's culpability of murder as a lesser included offense. In response to exceptions to this charge, the trial court reinstructed the jury that, if it found that "an extreme emotional disturbance had been established, that may be taken into consideration by you in determining whether or not capital felony murder has been established. You may determine it has not because of an extreme emotional disturbance . . . ." The defendant again excepted, claiming that the curative instruction was confusing.

On appeal, the defendant continues to maintain that the jury was inadequately instructed on the defense of extreme emotional disturbance, while the state maintains that extreme emotional disturbance is not a defense to a capital felony. The state relies on State v. Chicano, 216 Conn. 699, 716-17, 584 A.2d 425, cert. denied, 501 U.S. 1254, 111 S.Ct. 2898, 115 L.Ed.2d 1062 (1991), in which we held that extreme emotional defense is not an affirmative defense to felony murder as that crime is defined by General Statutes 53a-54c. We need not, however, resolve the applicability of the defense in this case. If the defense applies, the defendant received its benefit, because the trial court's supplemental instructions adequately informed the jury of its relationship to the capital felonies with which he was charged. The defendant cannot complain of alleged instructional misstatements that are corrected by a timely supplemental instruction. State v. Dolphin, 195 Conn. 444, 450-51, 488 A.2d 812, cert. denied, 474 U.S. 833, 106 S.Ct. 103, 88 L.Ed.2d 84 (1985); State v. Spates, 176 Conn. 227, 237, 405 A.2d 656, cert. denied, 440 U.S. 922, 99 S.Ct. 1248, 59 L.Ed.2d 475 (1979). Indeed, a supplemental charge is likely to enjoy special prominence in the minds of the jurors because it is fresher in their minds when they deliberate. State v. Williams, 199 Conn. 30, 41, 505 A.2d 699 (1986).

D

OTHER CLAIMS OF UNDUE PREJUDICE

In addition to the foregoing claims of impropriety at his trial, the defendant claims that he is entitled to a new trial because the trial court: (1) denied his motion for severance; (2) permitted prejudicial commentary by the prosecuting attorney; and (3) refused to overturn the verdicts against him on the ground of juror prejudice. We are not persuaded.

1

The defendant maintains that the trial court improperly denied his motion to sever the three cases that were consolidated for trial. He maintains that the state's joint presentation of the three cases so intermingled the evidence that the jury was encouraged to rely on a cumulation or aggregation of the evidence in arriving at its verdict. Because each of the cases charged the defendant with crimes that were factually similar and of a violent nature, he contends that the joint trial caused him irreparable prejudice and that the prejudice was not cured by the trial court's instruction to the jury to treat the three informations as three separate offenses.

The defendant's claim arose in the following procedural context. The trial court's initial ruling to consolidate the three cases against the defendant resulted from the defendant's express representation that he had no preference about whether the cases should be consolidated for trial. Approximately nine months later, the defendant stated on the record that he wanted to try the cases together. Subsequently, however, the defendant made a motion to sever the Rhode Island murders from the other two cases. That motion was premised on the defendant's expressed desire to testify concerning the jurisdictional facts relating to the Rhode Island murders. In fact, the defendant did not testify at trial.

Even though this procedural history does not definitively establish that the defendant has waived his claim for severance; State v. Herring, 210 Conn. 78, 97, 554 A.2d 686, cert. denied, 492 U.S. 912, 109 S.Ct. 3230, 106 L.Ed.2d 579 (1989); he cannot succeed on its merits. On appeal, our review of a trial court's order of consolidation is limited to determining whether the trial court has manifestly abused its discretion. State v. Jennings, 216 Conn. 647, 657, 583 A.2d 915 (1990); State v. Herring, supra, 94-95. In this case, the trial court could reasonably have concluded that the three cases involved charges that were factually discrete and easily distinguishable, that the violence involved in each of them would not have led to juror confusion or undue prejudice, and that the joint trial would not have substantially exacerbated the duration and the complexity of the trial. See State v. Boscarino, 204 Conn. 714, 722-23, 529 A.2d 1260 (1987). The defendant did not contest that he was the person who had killed each of the victims. His defense of insanity included references to all the killings, including those that had occurred in Windham county, with respect to which his guilt had already been established. In light of the insanity defense, of which the court had notice when it denied the motion to sever, the jury might well have received evidence about the Rhode Island killings even if those cases had been severed. See State v. Pollitt, 205 Conn. 61, 72, 530 A.2d 155 (1987). The defendant has, therefore, failed to meet his heavy burden of proving an abuse of discretion.

2

The defendant next claims that his constitutional rights were violated by a single statement during the prosecutor's closing argument. The prosecutor told the jury: "You have a defendant sitting in front of you — and just incidentally, you may take into account whatever you observe in this courtroom about the defendant Michael Ross in your deciding whether or not he was mentally ill at the time that he committed the offenses. You may take that into account." Although the defendant did not object to the prosecutor's argument at trial, he now maintains that we should review his claim under State v. Golding, 213 Conn. 233, 239-40, 567 A.2d 823 (1989), and find a violation of his due process rights and his rights to representation by counsel under the fifth and sixth amendments to the United States constitution.

While we have recognized the possibility that prosecutorial misconduct of constitutional proportions may arise during the course of closing argument, we have never held that a single questionable prosecutorial statement is sufficient to implicate the fairness of the trial itself. See State v. Joyner, supra, 225 Conn. 473; State v. Somerville, 214 Conn. 378, 393, 572 A.2d 944 (1990). Even if it were appropriate to grant broader review to some unpreserved claims in a death penalty case, this claim would not warrant such special consideration in the absence of a showing of significant prejudice. The defendant cannot prevail on this Golding claim.

3

The defendant's final contention with respect to his guilt of the crimes charged is that he presented sufficient evidence of juror prejudice to require the trial court to grant his motion to set aside the verdict and for a new trial. The motion was grounded principally on two allegations: (1) the jury's very brief period of deliberation; and (2) the conduct of one juror, who "smiled broadly" at the father of one of the victims at the time of the verdict. The defendant also informed the court that, following the verdict, the mother of one of the victims had verbally thanked the jury. The trial court denied the defendant's request for an evidentiary hearing into these allegations of prejudice and denied his motion on its merits.

"Appellate review of a trial court's decision granting or denying a motion for a new trial must take into account the trial judge's superior opportunity to assess the proceedings over which he or she has personally presided. . . . [W]e have . . . accordingly confined our role to a determination of whether there has been an abuse of discretion." State v. Hammond, 221 Conn. 264, 269-70, 604 A.2d 793 (1992). Claims of juror misconduct fall within this rule of limited review. State v. Asherman, 193 Conn. 695, 735-36, 478 A.2d 227, cert. denied 470 U.S. 1050, 105 S.Ct. 1749, 84 L.Ed.2d 814 (1985).

The fact that jury deliberations took only a little more than one hour does not establish the defendant's claim of juror prejudice. In the absence of a claim of external influence or juror misconduct, "[t]he length of time that a jury deliberates has no bearing on nor does it directly correlate to the strength or correctness of its conclusions or the validity of its verdict." State v. Hernandez, 28 Conn. App. 126, 136, 612 A.2d 88, cert. denied, 223 Conn. 920, 614 A.2d 828 (1992); State v. Dubina, 164 Conn. 95, 101, 318 A.2d 95 (1972).

The limited postverdict contacts between the jurors and the victims' parents similarly do not establish that there were any impermissible communications to or by the jurors during the course of the trial or during their deliberations. In response to the trial court's inquiry, the defendant acknowledged that he had no other information relevant to its allegations of juror prejudice. On this record, the defendant has offered insufficient allegations of actual bias to require the trial court either to hold an evidentiary hearing or to set aside the jury's verdict. State v. Almeda, 189 Conn. 303, 313, 455 A.2d 1326 (1983).

In summary, we have examined each of the defendant's claims relating to his guilt, under 53a-54b(5) and (7), of the six capital felony counts relating to his murder of Wendy B., Robyn S., April B. and Leslie S. We find no reason for reversing the verdicts of the jury on any of these counts.

II

FACIAL VALIDITY OF THE DEATH PENALTY STATUTE

The defendant next challenges the facial validity of the provisions of the death penalty statute both under the federal constitution and under the state constitution. Although the defendant also raises constitutional issues with respect to the application of 53a-46a in his particular circumstances, we will consider those issues, to the extent required, in part III of this opinion.

With respect to the federal constitution, the defendant maintains that 53a-46a impermissibly: (1) fails to provide for an individual decision by a capital sentencer; (2) fails to provide an opportunity for a full individualized consideration of himself as defendant; (3) requires the defendant to prove the existence of a mitigating factor by a preponderance of the evidence; (4) embodies a presumption that death is the appropriate penalty; (5) authorizes an aggravating factor that is unconstitutionally vague; and (6) requires juror unanimity before a mitigating factor can be given effect. In light of the governing federal precedents, we find none of these claims persuasive.

With respect to the state constitution, the defendant maintains that: (1) any imposition of the death penalty constitutes cruel and unusual punishment, and such a penalty is barred as a matter of substantive due process; and (2) the statutory procedures contained in 53a-46a violate procedural due process. We are not persuaded that state constitutional analyses or precedents support either of these claims.

A

FEDERAL CONSTITUTIONAL ISSUES

1

Analysis of the defendant's specific claims that our death penalty statute fails to conform to federal constitutional mandates must begin with an overview of the applicable law under the eighth and fourteenth amendments to the federal constitution. Since Gregg v. Georgia, 428 U.S. 153, 186-87, 96 S.Ct. 2909, 49 L.Ed.2d 859 (1976), the death penalty is not per se unconstitutional as a matter of federal law. As the United States Supreme Court stated in California v. Ramos, 463 U.S. 992, 999, 103 S.Ct. 3446, 77 L.Ed.2d 1171 (1983), "[i]n ensuring that the death penalty is not meted out arbitrarily or capriciously, the Court's principal concern has been more with the procedure by which the State imposes the death sentence than with the substantive factors the State lays before the jury as a basis for imposing death, once it has been determined that the defendant falls within the category of persons eligible for the death penalty." (Emphasis in original.)

Recognizing the unique nature of the death penalty and the need for heightened reliability in death penalty deliberations; Sumner v. Shuman, 483 U.S. 66, 72, 107 S.Ct. 2716, 97 L.Ed.2d 56 (1987); California v. Brown, 479 U.S. 538, 543, 107 S.Ct. 837, 93 L.Ed.2d 934 (1987); Caldwell v. Mississippi, 472 U.S. 320, 329, 105 S.Ct. 2633, 86 L.Ed.2d 231 (1985); California v. Ramos, supra, 463 U.S. 998-99; Roberts v. Louisiana, 428 U.S. 325, 333-36, 96 S.Ct. 3001, 49 L.Ed.2d 974 (1976); Woodson v. North Carolina, 428 U.S. 280, 303-306, 96 S.Ct. 2978, 49 L.Ed.2d 944 (1976); Jurek v. Texas, 428 U.S. 262, 271-72, 96 S.Ct. 2950, 49 L.Ed.2d 929 (1976); Proffitt v. Florida, 428 U.S. 242, 252-53, 96 S.Ct. 2960, 49 L.Ed.2d 913 (1976); Gregg v. Georgia, supra, 428 U.S. 188-95; the United States Supreme Court has derived from the eighth amendment's proscription of cruel and unusual punishment two principal prerequisites to assure the propriety of the imposition of the death penalty in any particular case. "First, sentencers may not be given unbridled discretion in determining the fates of those charged with capital offenses. The Constitution instead requires that death penalty statutes be structured so as to prevent the penalty from being administered in an arbitrary and unpredictable fashion. . . . Second, even though the sentencer's discretion must be restricted, the capital defendant generally must be allowed to introduce any relevant mitigating evidence regarding his character or record and any of the circumstances of the offense. . . . Consideration of such evidence is a constitutionally indispensable part of the process of inflicting the penalty of death." (Citations omitted; internal quotation marks omitted.) California v. Brown, supra, 541. "[A] system of capital punishment [must be] at once consistent and principled but also humane and sensible to the uniqueness of the individual. . . . [It must] serve both goals of measured, consistent application and fairness to the accused." Eddings v. Oklahoma, 455 U.S. 104, 110-11, 102 S.Ct. 869, 71 L.Ed.2d 1 (1982); see also Spaziano v. Florida, 468 U.S. 447, 459-60, 104 S.Ct. 3154, 82 L.Ed.2d 340 (1984).

The first prerequisite prohibiting unbridled discretion requires death penalty statutes to be structured so that the death penalty is imposed in a consistent and reliable manner. In deciding to authorize capital punishment, a state "has a constitutional responsibility to tailor and apply its law in a manner that avoids the arbitrary and capricious infliction of the death penalty [including] defin[ing] the crimes for which death may be the sentence in a way that obviates standardless sentencing discretion." (Internal quotation marks omitted.) Godfrey v. Georgia, 446 U.S. 420, 428, 100 S.Ct. 1759, 64 L.Ed.2d 398 (1980). A statutory requirement that, before death may be imposed, the sentencer must find at least one statutorily mandated aggravating circumstance is a constitutionally permissible response to the need to avoid standardless sentencing discretion and to narrow the class of persons eligible for the death penalty. Blystone v. Pennsylvania, 494 U.S. 299, 302, 110 S.Ct. 1078, 108 L.Ed.2d 255 (1990); Lowenfield v. Phelps, 484 U.S. 231, 244, 108 S.Ct. 546, 98 L.Ed.2d 568 (1988); Jurek v. Texas, supra, 428 U.S. 270-71, 276; Proffitt v. Florida, supra, 428 U.S. 251-53; Gregg v. Georgia, supra, 428 U.S. 198.

The eighth amendment's mandate that the death penalty may only be imposed in a manner that is consistent and reliable also imposes other conditions on the validity of a death penalty statute. A constitutional concern for accurate sentencing information requires that the defendant be afforded access to and an opportunity to rebut all relevant sentencing information. Gardner v. Florida, 430 U.S. 349, 357-58, 97 S.Ct. 1197, 51 L.Ed.2d 393 (1977) (plurality opinion); Gregg v. Georgia, supra, 428 U.S. 190. To focus attention on the importance of sentencing decisions, a death penalty may not constitutionally be imposed without a bifurcated hearing that addresses the appropriate sentence separately from the determination of guilt. Gregg v. Georgia, supra, 190-92, 195. Finally, to provide a check against having a death sentence imposed under the influence of passion or prejudice, or in a random and arbitrary manner, there must be an opportunity for meaningful appellate review. Jurek v. Texas, supra, 428 U.S. 276; Proffitt v. Florida, supra, 428 U.S. 258-60; Gregg v. Georgia, supra, 198, 207; see also Pulley v. Harris, 465 U.S. 37, 44-45, 104 S.Ct. 871, 79 L.Ed.2d 29 (1984) (proportionality review not constitutionally required).

The second prerequisite for a valid death penalty statute is that, in addition to achieving consistency and reliability, it must also focus the sentencer's attention on "the character and record of the individual offender and the circumstances of the particular offense. . . ." Woodson v. North Carolina, supra, 428 U.S. 304. "`[T]he Eighth and Fourteenth Amendments require that the sentencer . . . not be precluded from considering, as a mitigating factor, any aspect of a defendant's character or record and any of the circumstances of the offense that the defendant proffers as a basis for a sentence less than death.'" (Emphasis in original.) Eddings v. Oklahoma, supra, 455 U.S. 110, quoting Lockett v. Ohio, 438 U.S. 586, 604, 98 S.Ct. 2954, 57 L.Ed.2d 973 (1978) (Burger, C.J., for plurality); see also Payne v. Tennessee, 501 U.S. 808, 822, 111 S.Ct. 2597, 2606, 115 L.Ed.2d 720, reh. denied, 501 U.S. 1277, 112 S.Ct. 28, 115 L.Ed.2d 1110 (1991); Sumner v. Shuman, supra, 483 U.S. 75-76; Hitchcock v. Dugger, 481 U.S. 393, 394, 107 S.Ct. 1821, 95 L.Ed.2d 347 (1987); Skipper v. South Carolina, 476 U.S. 1, 4, 106 S.Ct. 1669, 90 L.Ed.2d 1 (1986); Zant v. Stephens, 462 U.S. 862, 879, 103 S.Ct. 2733, 77 L.Ed.2d 235 (1983); Jurek v. Texas, supra, 428 U.S. 271-72; Gregg v. Georgia, supra, 428 U.S. 189. The sentence imposed at the penalty stage "should reflect a reasoned moral response to the defendant's background, character, and crime." (Emphasis in original; internal quotation marks omitted.) Penry v. Lynaugh, 492 U.S. 302, 319, 109 S.Ct. 2934, 106 L.Ed.2d 256 (1989). "In contrast to the carefully defined standards that must narrow a sentencer's discretion to impose the death sentence, the Constitution limits a State's ability to narrow a sentencer's discretion to consider relevant evidence that might cause it to decline to impose the death sentence." (Emphasis in original.) McCleskey v. Kemp, 481 U.S. 279, 304, 107 S.Ct. 1756, 95 L.Ed.2d 262 (1987).

Although this second prerequisite demands that the sentencer "`must be able to consider and give effect to any mitigating evidence relevant to a defendant's background and character or the circumstances of the crime'"; Blystone v. Pennsylvania, supra, 494 U.S. 304-305, quoting Penry v. Lynaugh, supra, 492 U.S. 328; the federal constitution does not require "unfettered sentencing discretion. . . . States are free to structure and shape consideration of mitigating evidence in an effort to achieve a more rational and equitable administration of the death penalty." (Internal quotation marks omitted.) Boyde v. California, 494 U.S. 370, 377, 110 S.Ct. 1190, 108 L.Ed.2d 316, reh. denied, 495 U.S. 924, 110 S.Ct. 1961, 109 L.Ed.2d 322 (1990); Saffle v. Parks, 494 U.S. 484, 492-93, 110 S.Ct. 1257, 108 L.Ed.2d 415, reh. denied, 495 U.S. 924, 110 S.Ct. 1960, 109 L.Ed.2d 322 (1990). Federal precedents have upheld the constitutionality of state statutes that, like our own, permit the imposition of the death penalty: (1) if the sentencer finds the existence of at least one aggravating factor and no mitigating factor, as long as the sentencer could consider a broadly phrased and nonexclusive list of mitigating factors; Boyde v. California, supra, 373-78; Blystone v. Pennsylvania, supra, 304-307; and (2) if the sentencer finds that the defendant has not proved the existence of a mitigating factor by a preponderance of the evidence. Walton v. Arizona, 497 U.S. 639, 649-51, 110 S.Ct. 3047, 111 L.Ed.2d 511, reh. denied, 497 U.S. 1050, 111 S.Ct. 14, 111 L.Ed.2d 828 (1990); Blystone v. Pennsylvania, supra, 306 n. 4. The determination of whether death is the appropriate punishment should be based on a "reasoned moral response . . . rather than an emotional one." (Citation omitted; Internal quotation marks omitted.) Saffle v. Parks, supra, 493; California v. Brown, supra, 479 U.S. 542-43.

"In sum, [the United States Supreme Court's] decisions [regarding its eighth amendment jurisprudence] since Furman [v. Georgia, 408 U.S. 238, 92 S.Ct. 2726, 33 L.Ed.2d 346 (1972),] have identified a constitutionally permissible range of discretion in imposing the death penalty. First, there is a required threshold below which the death penalty cannot be imposed. In this context, the State must establish rational criteria that narrow the decisionmaker's judgment as to whether the circumstances of a particular defendant's case meet the threshold. Moreover, a societal consensus that the death penalty is disproportionate to a particular offense prevents a State from imposing the death penalty for that offense. Second, States cannot limit the sentencer's consideration of any relevant circumstances that could cause it to decline to impose the penalty. In this respect, the State cannot channel the sentencer's discretion, but must allow it to consider any relevant information offered by the defendant." McCleskey v. Kemp, supra, 481 U.S. 305-306.

2

Bearing these federal constitutional principles in mind, we now turn to an assessment of the facial validity of our death penalty statutes in light of the defendant's claims. The defendant claims that 53a-46a is unconstitutional on its face because it: (1) fails to provide for an individual decision by a capital sentencer; (2) fails to provide an opportunity for a full individualized consideration of himself as defendant; (3) requires the defendant to prove the existence of a mitigating factor by a preponderance of the evidence; (4) embodies a presumption that death is the appropriate penalty; (5) authorizes an aggravating factor that is unconstitutionally vague; and (6) requires juror unanimity before a mitigating factor can be given effect. We disagree.

In our assessment of whether the statute passes constitutional muster, we proceed from the well recognized jurisprudential principle that "[t]he party attacking a validly enacted statute . . . bears the heavy burden of proving its unconstitutionality beyond a reasonable doubt and we indulge in every presumption in favor of the statute's constitutionality. . . . In choosing between two constructions of a statute, one valid and one constitutionally precarious, we will search for an effective and constitutional construction that reasonably accords with the legislature's underlying intent. . . . We undertake this search for a constitutionally valid construction when confronted with criminal statutes as well as with civil statutes." (Citations omitted.) State v. Breton, 212 Conn. 258, 269, 562 A.2d 1060 (1989). The burden of proving unconstitutionality is especially heavy when, as at this juncture, a statute is challenged as being unconstitutional on its face. State v. Floyd, 217 Conn. 73, 78, 584 A.2d 1157 (1991).

We cannot review the defendant's specific claims of unconstitutionality without placing them into the context of our death penalty statutory provisions as a whole. In General Statutes 53a-46a through 53a-46c, the legislature has established a three-tiered pyramid, in which each tier narrows the class of defendants that may be found eligible for the death penalty. At the first tier above the base of the pyramid, our statute separates capital felony homicides from other homicides, and authorizes bifurcated death penalty hearings only for those who have been found guilty of or have pleaded guilty to a capital felony. General Statutes 53a-46a(b). At the second tier, the statute further limits the death penalty by requiring the sentencer to find, beyond a reasonable doubt, the existence of at least one statutorily delineated aggravating factor. General Statutes 53a-46a(b), (e), (i) and (h). State v. Daniels, 207 Conn. 374, 384, 542 A.2d 306 (1988). At the third and final tier, our statute "`separates, from all cases in which a penalty of death may be imposed, those cases in which it shall be imposed'"; Zant v. Stephens, supra, 462 U.S. 871; by requiring a sentencer to find, by a preponderance of the evidence, whether a mitigating factor exists. General Statutes 53a-46a(e). In making this determination, the capital sentencer must consider the existence of each of the mitigating factors listed in the statute at 53a-46a(g) and of any other "mitigating factor concerning the defendant's character, background and history, or the nature and circumstances of the crime." General Statutes 53a-46a(b). If the sentencer fails to find the existence of a mitigating factor, after having found the existence of an aggravating factor, the court must sentence the defendant to death. General Statutes 53a-46a(f). Otherwise, the court must impose a sentence of life imprisonment without possibility of release.

In their overall configuration, our death penalty statutes facially satisfy the constitutional requirements of the eighth and fourteenth amendments to the United States constitution. The multitiered pyramid meets the prerequisite of consistency and reliability by guiding the capital sentencer's discretion with clear and objective standards that narrow the class of defendants eligible for the death penalty and by providing a meaningful basis for distinguishing between those cases in which the death penalty is imposed and those in which it is not. The third tier in the pyramid meets the individualization prerequisite by requiring the sentencer to consider any relevant mitigating information so as to enable the sentencer to make the reasoned moral judgment that death is the appropriate punishment in a particular case. See Walton v. Arizona, supra, 497 U.S. 647-49; Boyde v. California, supra, 494 U.S. 373-78; Blystone v. Pennsylvania, supra, 494 U.S. 305; Zant v. Stephens, supra, 462 U.S. 879; Eddings v. Oklahoma, supra, 455 U.S. 110-12; Lockett v. Ohio, supra, 438 U.S. 601-605; Gregg v. Georgia, supra, 428 U.S. 189. Notably, because our statute does not permit the weighing of aggravating and mitigating factors but permits the death sentence to be imposed only if no mitigating circumstances are found; General Statutes 53a-46a(e) and (f); it is more stringent than the Pennsylvania sentencing statute that was found constitutional in Blystone v. Pennsylvania, supra, 299. Furthermore, because our statute mandates this court's review of the relevant factual findings and scrutiny of the record to assure that the death penalty was not "the product of passion, prejudice or any other arbitrary factor"; General Statutes 53a-46b; it satisfies the constitutional requirement of meaningful appellate review. Gregg v. Georgia, supra, 198, 207.

The defendant, however, raises six specific constitutional challenges to the facial validity of our death penalty statutes. The defendant's first two claims are interrelated. He claims both that our death penalty sentencing system fails to provide for an individualized decision that the death penalty is the appropriate sentence by an appropriate sentencer; and that our sentencing system imposes a mandatory death sentence on a particular class of defendants without the full, individualized consideration by the sentencer of whether death is the appropriate penalty for each defendant. As a facial challenge to the validity of our death penalty sentencing statutes, these claims of a lack of appropriately guided discretion are not tenable under the federal constitution.

The United States Supreme Court has stated that the capital sentencer must make a reasoned moral and individualized determination based on the defendant's background, character and crime that death is the appropriate punishment. Penry v. Lynaugh, supra, 492 U.S. 319; Caldwell v. Mississippi, supra, 472 U.S. 330-32; see also Saffle v. Parks, supra, 494 U.S. 492-93; California v. Brown, supra, 479 U.S. 541, 543. Our death penalty statutes fulfill this requirement.

Under 53a-46a(b), the capital sentencer is either a jury or the court. The sentencer determines whether the defendant, who has been convicted of a capital felony, should receive the punishment of death by making findings regarding the existence of any aggravating or mitigating factors. General Statutes 53a-46a(e). The requirement that the sentencer's determination be made by setting forth its findings regarding aggravating and mitigating factors merely guides the sentencer's discretion to achieve a more focused and rational response. Boyde v. California, supra, 494 U.S. 377; Blystone v. Pennsylvania, supra, 494 U.S. 304-305.

The sentencer makes the required moral and individualized determination, under our statute, because it must consider a nonexclusive list of mitigating factors as well as a catchall category consisting of any other "mitigating factor concerning the defendant's character, background and history, or the nature and circumstances of the crime." General Statutes 53a-46a(b) and (f). The catchall category of mitigating factors includes those factors "which, in fairness and mercy, may be considered as tending either to extenuate or reduce the degree of [the defendant's] culpability or blame for the offense or to otherwise constitute a basis for a sentence less than death." General Statutes 53a-46a(d). The ability to consider an unrestricted set of mitigating factors satisfies federal constitutional requirements for a moral and individualized decision. Blystone v. Pennsylvania, supra, 494 U.S. 305.

Furthermore, it is evident that the capital sentencer, either a jury or the court, in making its determination regarding the existence of aggravating and mitigating factors during the separate sentencing hearing is aware that its "task [is] the serious one of determining whether a specific human being should die at the hands of the State." Caldwell v. Mississippi, supra, 472 U.S. 329. Finally, the death sentence is mandatorily imposed only after the capital sentencer has determined unanimously that at least one aggravating factor exists and no mitigating factors exist, and has come to this unanimous determination by engaging in a full, individualized consideration as to whether death is the appropriate penalty for each defendant. Blystone v. Pennsylvania, supra, 494 U.S. 303-305.

We conclude, therefore, that our capital sentencing statutes, on their face, give the capital sentencer, either a jury or the court, the proper amount of guided discretion to make the appropriate determination regarding the individual defendant with regard to the defendant's specific crime. Because the statutes are not impermissibly mandatory, they comply with the eighth and the fourteenth amendments to the United States constitution.

The defendant's next two claims are that our death penalty statute is facially unconstitutional because, first, as construed in State v. Daniels, supra, 207 Conn. 385, the statute requires the defendant to prove the existence of a mitigating factor by a preponderance of the evidence and, second, the statute embodies a presumption of death once the state proves the existence of an aggravating factor. Both claims are foreclosed by the United States Supreme Court's recent decision in Walton v. Arizona, supra, 497 U.S. 649-52.

The defendant next claims that the aggravating factor that the state charged, and that the jury found to have been proven in this case, is unconstitutionally vague on its face. The 53a-46a(h)(4) aggravating factor provides that "[i]f no mitigating factor is present, the court shall impose the sentence of death on the defendant if the jury . . . finds . . . that . . . the defendant committed the offense in an especially heinous, cruel or depraved manner." (Emphasis added.) The United States Supreme Court has held the terms, "heinous, atrocious, or cruel," to be unconstitutionally vague; Maynard v. Cartwright, 486 U.S. 356, 363-65, 108 S.Ct. 1853, 100 L.Ed.2d 372 (1988); see also Godfrey v. Georgia, supra, 446 U.S. 428-33 (holding the terms "outrageously or wantonly vile, horrible or inhuman" as unconstitutionally vague); unless they have been appropriately construed and limited by the state's court. Maynard v. Cartwright, supra, 359-60; Godfrey v. Georgia, supra, 428-29; Proffitt v. Florida, supra, 428 U.S. 255-56. In State v. Breton, supra, 212 Conn. 270, we adopted a limiting definition of the term "especially cruel" in our construction of the 53a-46a(h)(4) aggravating factor. Similarly, the terms "heinous" and "depraved" are susceptible of limiting constructions in conjunction with our definition of "especially cruel." See part III A 1. So construed, 53a-46a(h)(4) is not unconstitutionally vague under the eighth and fourteenth amendments to the federal constitution.

The defendant's final claim is that our death penalty system, as construed in State v. Daniels, supra, 207 Conn. 374, is facially unconstitutional because it requires the jury to be unanimous in finding the existence of a mitigating factor before an individual juror can give effect to any mitigating factor. The defendant finds support for his position in McKoy v. North Carolina, 494 U.S. 433, 110 S.Ct. 1227, 108 L.Ed.2d 369 (1990), in which North Carolina's death penalty sentencing statute was held to be unconstitutional because the jury, acting as the capital sentencer, could consider only those mitigating circumstances found unanimously when it weighed mitigating circumstances against aggravating circumstances in deciding whether to impose the death penalty. This unanimity requirement was declared to be unconstitutional because it impermissibly prevented each juror from considering and giving effect to all mitigating evidence. Id., 437-38.

Although in State v. Daniels, supra, 207 Conn. 388-89, we held that the jury had to be unanimous in its finding that the defendant had proven the existence of a mitigating factor by a preponderance of the evidence, that holding arose in the context of a hung jury. In those circumstances, we stated that, in "death penalty cases in which a trier of fact cannot come to a unanimous finding about the existence of mitigating factors. . . . [T]he statute neither authorizes imposition of the death penalty nor requires the imposition of a life sentence. . . . [T]he imposition of the death penalty under 53a-46a(e) must be premised on two unanimous findings by the trier of fact: that the state has proved beyond a reasonable doubt that an aggravating factor exists and that the defendant has not proved by a preponderance of the evidence that a mitigating factor exists. A unanimous jury verdict that the defendant did not prove that a mitigating factor exists fulfills the statutory requirement that the death penalty not be imposed unless `no mitigating factors exist' within the meaning of 53a-46a(e). . . . Faced with a jury that is unable to agree unanimously on its findings, the trial court may, in the exercise of its discretion, grant a motion for mistrial [pursuant to Practice Book 889,] by either party [or] enter a judgment `acquitting' the defendant of the death penalty [pursuant to Practice Book 883."] Id., 394-96.

Our holding in Daniels did not imply that individual jurors are precluded from considering and giving effect to all mitigating evidence in a death penalty sentencing hearing. The unanimity requirement in our statute requires unanimity only in the sense that each juror must find at least one mitigating factor that was proved by a preponderance of the evidence. The jury need not unanimously find the same mitigating factor to have been proven by a preponderance of the evidence. So construed, our death penalty sentencing statute avoids the unanimity problem identified in McKoy, because our unanimity requirement does not interfere with the ability of each individual juror to consider and to give effect to any mitigating factor of which he or she is convinced by a preponderance of the evidence. McKoy v. North Carolina, supra, 494 U.S. 439-44. With respect to this claim as well, therefore, we conclude that our death penalty statutes are not unconstitutional on their face as a matter of federal constitutional law.

B

STATE CONSTITUTIONAL ISSUES

The defendant contends, in the alternative, that our death penalty statutes facially violate article first, 8 and 9 of the state constitution. This contention is advanced on two theories. Broadly, the defendant maintains that our state constitution impliedly forbids any punishment that is cruel and unusual and that imposition of the death penalty invariably constitutes cruel and unusual punishment. More narrowly, the defendant maintains that certain specific statutory procedures contained in 53a-46a violate procedural due process as defined by the state constitution. We are not persuaded that applicable state constitutional analyses or precedents support either claim.

1

The defendant broadly claims that our state constitution forbids any imposition of the death penalty because such a penalty, regardless of the circumstances, constitutes cruel and unusual punishment. He maintains that a proper construction of the provisions of our state constitution requires rejection of the contrary holding of the United States Supreme Court in Gregg v. Georgia, supra, 428 U.S. 153. We disagree.

In order to resolve this claim, we must address two issues. We must first decide whether our state constitution contains any prohibition of cruel and unusual punishment. If that question is decided in the affirmative, we must then decide whether imposition of the death penalty invariably violates such a constitutional prohibition.

Unlike the eighth amendment to the federal constitution, no provision in our state constitution specifically proscribes cruel and unusual punishment. Nonetheless, we are free to interpret the due process guarantees contained in our state constitution to prohibit governmental infliction of cruel and unusual punishments. See State v. Kreminski, 178 Conn. 145, 153 and n. 4, 422 A.2d 294 (1979); State v. Kyles, 169 Conn. 438, 442-44, 363 A.2d 97 (1975).

In determining the scope of our state constitution's due process clauses, we have taken as a point of departure those constitutional or quasi-constitutional rights that were recognized at common law in this state prior to 1818. This is the analysis that we undertook when the question was whether our state constitution protects criminal defendants from double jeopardy. Despite the absence of an express constitutional provision on the subject, we held that our due process clause impliedly includes a right to protection against double jeopardy, because protection against double jeopardy was recognized as a fundamental right in the common law of this state. State v. Rawls, 198 Conn. 111, 113 n. 3, 502 A.2d 374 (1985); Kohlfuss v. Warden, 149 Conn. 692, 695, 183 A.2d 626, cert. denied, 371 U.S. 928, 83 S.Ct. 298, 9 L.Ed.2d 235 (1962); see also E. Peters, "Common Law Antecedents of Constitutional Law in Connecticut," 53 Alb. L. Rev. 259 (1989).

Applying the same analysis to this case, we are persuaded that our due process clauses impliedly prohibit punishment that is cruel and unusual. Prior to the adoption of the state constitution in 1818, the common law in Connecticut recognized that the state did not have unlimited authority to inflict punishment for the commission of a crime. See State v. Smith, 5 Day (Conn.) 175, 178-79 (1811); see also 2 Z. Swift, A Digest of the Laws of the State of Connecticut (1822) pp. 268-69, 362, 418-19 ("[A]nd though the law invests goalers with all the powers necessary for the interest of the commonwealth, yet they are not to behave with the least degree of wanton cruelty to their prisoners"; rules against execution of the insane and pregnant women. Accordingly, we have routinely assumed that our constitution includes a prohibition against cruel and unusual punishment. State v. Dupree, 196 Conn. 655, 665, 495 A.2d 691, cert. denied, 474 U.S. 951, 106 S.Ct. 318, 88 L.Ed.2d 301 (1985); State v. Kreminski, supra, 178 Conn. 1 53 and n. 4 (article first, 8); State v. Kyles, supra, 169 Conn. 442-44 (article first, 9); State v. Levy, 103 Conn. 138, 148, 130 A. 96 (1925)(unspecified); cf. Cinque v. Boyd, 99 Conn. 70, 94-95, 121 A. 678 (1923) (article first, 10, now 9, pertaining to juvenile detention). The state does not seriously argue to the contrary.

The unresolved question is whether, construed to bar punishment that is cruel and unusual, the due process clauses of our state constitution forbid any enactment of a death penalty for all cases and under all circumstances. Before addressing the merits of that question, we note preliminarily that our state constitutional inquiry may proceed independently from the decisions of the United States Supreme Court upholding the constitutionality of the death penalty. "We may find greater protection of individual rights under our state constitution than that provided by the federal constitution. It is well established that federal constitutional law establishes a minimum national standard for the exercise of individual rights and does not inhibit state governments from affording higher levels of protection for such rights. . . . Moreover, we have held that in the area of fundamental civil liberties — which includes all protections of the declaration of rights contained in article first of the Connecticut constitution — we sit as a court of last resort. In such constitutional adjudication, our first referent is Connecticut law and the full panoply of rights Connecticut citizens have come to expect as their due. Accordingly, decisions of the United States Supreme Court defining fundamental rights are persuasive authority to be afforded respectful consideration, but they are to be followed by Connecticut courts only when they provide no less individual protection than is guaranteed by Connecticut law. . . Recognizing that our state constitution is an instrument of progress . . . is intended to stand for a great length of time and should not be interpreted too narrowly or too literally . . . we have concluded in several cases that the state constitution provides broader protection of individual rights than does the federal constitution." (Citations omitted; internal quotation marks omitted.) State v. Miller, 227 Conn. 363, 379-80, 630 A.2d 1315 (1993).

The defendant urges us to exercise our independent authority under the state constitution to declare any imposition of the death penalty invalid as cruel and inhuman punishment because it no longer comports with contemporary standards of decency and civilization. He maintains that the death penalty can never be constitutional for three overlapping reasons: the death penalty violates the fundamental value and dignity of life itself; it cannot be carried out without the infliction of inhuman pain; and it serves no valid or compelling state purpose. The state urges us to conclude to the contrary, for two related reasons: the prohibition of cruel and inhuman punishment is grounded solely in article first, 9; and, as a matter of constitutional history and contrary to State v. Lamme, 216 Conn. 172, 178-82, 579 A.2d 484 (1990), article first, 9, confers the authority to determine what constitutes cruel and unusual punishment solely on the Connecticut legislature and not on the courts.

If the state were correct in its construction of our constitutional prohibition of cruel and inhuman punishment, that would end the matter. We are not, however, prepared to overlook article first, 8, as a constitutional basis for the prohibition. We are likewise unprepared to overrule our holding in Lamme that, in contemporary constitutional jurisprudence, article first, 9, has "independent substantive significance" that may protect constitutional rights not embodied in the form of a statute. State v. Lamme, supra, 216 Conn. 182; see State v. White, 229 Conn. 125, 152-55, 640 A.2d 572 (1994). Although we should exercise our authority with great restraint, this court cannot abdicate its nondelegable responsibility for the adjudication of constitutional rights.

We turn therefore to the defendant's contention that we should declare the death penalty to be unconstitutionally unacceptable on its face. In our analysis of issues arising, for the first time, under the state constitution, we have identified six factors to be considered: (1) the text of the constitutional provisions; (2) related Connecticut precedents; (3) persuasive federal precedents; (4) persuasive precedents of other state courts; (5) historical insights into the intent of our constitutional forbearers; and (6) contemporary understandings of applicable economic and sociological norms. State v. Geisler, 222 Conn. 672, 684-86, 610 A.2d 1225 (1992).

The first five factors do not support the defendant's argument. In article first, 8, and article first, 19, our state constitution makes repeated textual references to capital offenses and thus expressly sustains the constitutional validity of such a penalty in appropriate circumstances. Connecticut case law has recognized the facial constitutionality of the death penalty under the eighth and fourteenth amendments to the federal constitution. See, e.g., State v. Davis, 158 Conn. 341, 358, 260 A.2d 587 (1969), vacated and remanded on other grounds, Davis v. Connecticut, 408 U.S. 935, 92 S.Ct. 2856, 33 L.Ed.2d 750 (1972). Federal constitutional law does not forbid such a statute outright. Gregg v. Georgia, supra, 428 U.S. 153. Courts in the overwhelming majority of our sister states have rejected facial challenges to the death penalty under their state constitutions. Finally, Connecticut's history has included a death penalty statute since 1650, when it was incorporated into Ludlow's Code; see 3 N. Osborn, History of Connecticut (1925) pp. 24-25; and such a penalty was considered constitutional at the time of the adoption of the constitution of 1818.

We must therefore decide whether contemporary understandings of applicable economic and sociological norms compel the conclusion that any death penalty constitutes cruel and unusual punishment. The question is not whether any one of us would vote to enact a death penalty if our role were that of a legislator. It is, rather, whether the defendant is correct in his contention that the death penalty is so inherently cruel and so lacking in moral and sociological justification that it is unconstitutional on its face because it is fundamentally offensive to evolving standards of human decency. Stated so categorically, we are unpersuaded by the defendant's contention. Judicial evaluation of evolving standards of human decency cannot proceed in a vacuum. Community standards of acceptable legislative policy choices are necessarily reflected in the text of our constitutional document, in our history and in the teachings of the jurisprudence of our sister states as well as that of the federal courts. While we should not blindly follow a beaten path, we agree with the New Jersey Supreme Court's cogent observation: "When, in the course of a decade, thirty-seven states call for the death penalty, the probability that the legislature of each state accurately reflects its community's standards approaches certainty." State v. Ramseur, 106 N.J. 123, 173, 524 A.2d 188 (1987).

To say that imposition of the death penalty is not cruel and unusual punishment in all circumstances is not to say, however, that the death penalty can be imposed without any constitutional constraints. Community standards of acceptable legislative choices do not go that far. In State v. Lamme, supra, 216 Conn. 184, we observed that "federal constitutional precedents [may] appropriately illuminate open textured provisions in our own organic document" and that reasoned adoption of such precedents "in no way compromises our obligation independently to construe the provisions of our state constitution." Accordingly, we hold that the due process clauses of our state constitution incorporate the principles underlying a constitutionally permissible death penalty statute that the United States Supreme Court has articulated in cases such as California v. Brown, supra, 479 U.S. 541, Eddings v. Oklahoma, supra, 455 U.S. 110-12, and Lockett v. Ohio, supra, 438 U.S. 602-605. These principles require, as a constitutional minimum, that a death penalty statute, on the one hand, must channel the discretion of the sentencing judge or jury so as to assure that the death penalty is being imposed consistently and reliably and, on the other hand, must permit the sentencing judge or jury to consider, as a mitigating factor, any aspect of the individual defendant's character or record as well as the circumstances of the particular offense. Our death penalty statute, 53a-46a, meets these minimum state constitutional law requirements.

2

In addition to his contention that the death penalty violates the constitutional prohibition of cruel and unusual punishment, the defendant also challenges several specific provisions of 53a-46a as facially unconstitutional as a matter of due process under the state constitution. These claims can be grouped as follows. First, the death penalty statutes violate due process because they fail to provide for an individualized decision maker, or for an individualized decision about the propriety of the death sentence in any particular case. Second, the death penalty statute unconstitutionally requires the defendant to prove the existence of a mitigating factor and thereby embodies a presumption of death. Third, the aggravating factor that the defendant committed the capital felony "in an especially heinous, cruel or depraved manner"; General Statutes 53a-46a(h)(4); is unconstitutionally vague. Fourth, the requirement of juror unanimity in finding the existence of a mitigating factor unconstitutionally requires jurors to agree on the weight that each will assign to mitigating evidence. These claims mirror the specific contentions that the defendant raised as a matter of federal constitutional law and that we have found unpersuasive in light of the applicable federal precedents. We find them equally unpersuasive as a matter of state constitutional law.

The defendant's state constitutional claims that 53a-46a lacks the required individualized decision maker and the required individualized decision to impose the death penalty are misconstructions of the structure of the statute. As we noted in discussing this claim under the federal constitution, our statute identifies the capital sentencer as being either the jury or the court. The statute thereafter provides the capital sentencer with sufficient latitude to make a reasoned moral and individualized determination, based on the defendant's background, character and crime, that death is the appropriate punishment. See part II A. The statute enables a jury, with appropriate instructions, to make this awesome decision in a manner that is appropriately wide-angled and open-textured. So construed, the statute is "entirely consonant with the general contours of a constitutional safeguard rooted in flexible principles of due process." State v. Lamme, supra, 216 Conn. 178; State v. Joyner, 225 Conn. 450, 470-72, 625 A.2d 791 (1993). Other state courts have come to the same conclusion. People v. Brown, 40 Cal.3d 512, 538-44, 726 P.2d 516, 230 Cal.Rptr. 834 (1986), rev'd on other grounds, 479 U.S. 538, 107 S.Ct. 837, 93 L.Ed.2d 934 (1987); State v. Bey, 112 N.J. 123, 162-63, 548 A.2d 887 (1988).

The defendant maintains that 53a-46a facially violates his right to due process because, as that statute was construed in State v. Daniels, supra, 207 Conn. 383, he bore the burden of establishing the existence of a mitigating factor by a preponderance of the evidence. Assigning this burden of proof to him, he maintains, is per se unconstitutional and means that the statute in effect embodies a presumption of death whenever the jury finds that an aggravating factor has been established. We rejected a similar argument in State v. Joyner, supra, 225 Conn. 470-72, in which we found no constitutional impediment to requiring a defendant to bear the burden of proving his insanity. In Joyner, we found it significant that a "defendant is much more likely than the state to be able to produce reliable evidence of his own mental status." Id., 471-72. That reasoning applies equally to the defendant's superior access to mitigating information in a death penalty case. The defendant's claim to the contrary has been rejected not only by the United States Supreme Court in Walton v. Arizona, supra, 497 U.S. 639, but also by a substantial number of state courts. See State v. Richmond, 136 Ariz. 312, 316, 666 P.2d 57, cert. denied, 464 U.S. 986, 104 S.Ct. 435, 78 L.Ed.2d 367 (1983); State v. Charboneau, 116 Idaho 129, 154, 774 P.2d 299 (1989), overruled in part on other grounds, State v. Card, 121 Idaho 425, 825 P.2d 1081 (1991); People v. Bean, 137 Ill.2d 65, 138-40, 560 N.E.2d 258 (1990), cert. denied, 499 U.S. 932, 111 S.Ct. 1338, 113 L.Ed.2d 270 (1991); Ake v. State, 663 P.2d 1, 10-11 (Okla.Crim.App. 1983), rev'd on other grounds, 470 U.S. 68, 105 S.Ct. 1087, 84 L.Ed.2d 53 (1985). We concur with their holdings that, once guilt has been established and the state has proved the existence of an aggravating factor, "due process is not offended by requiring the already guilty defendant to carry the burden of showing why he should receive leniency." State v. Watson, 120 Ariz. 441, 447, 586 P.2d 1253 (1978), cert. denied, 440 U.S. 924, 99 S.Ct. 1254, 59 L.Ed.2d 478 (1979).

The defendant next claims that the death penalty statute is unconstitutionally vague because of inherent ambiguity in the aggravating factor contained in 53a-46a(h)(4). We have addressed this claim in State v. Breton, supra, 212 Conn. 268-71, by requiring death penalty jurors to be given appropriately limiting instructions to correct the unconstitutional infirmity in the phrase "in an especially heinous, cruel or depraved manner." Such limiting instructions have been upheld elsewhere, both as a matter of federal law; Maynard v. Cartwright, supra, 486 U.S. 359-60; Godfrey v. Georgia, supra, 446 U.S. 428-29; Proffitt v. Florida, supra, 428 U.S. 255-56; and as a matter of state law. See, e.g., State v. Greenway, 170 Ariz. 155, 165-67, 823 P.2d 22 (1991); State v. Dixon, 283 So.2d 1, 9 (Fla. 1973), cert. denied sub nom. Hunter v. Florida, 416 U.S. 943, 94 S.Ct. 1950, 40 L.Ed.2d 295 (1974); State v. Charboneau, supra, 116 Idaho 151-53; State v. Sonnier, 402 So.2d 650, 658-59 (La. 1981), cert. denied, 463 U.S. 1229, 103 S.Ct. 3571, 77 L.Ed.2d 1412 (1983); State v. Ryan, 233 Neb. 74, 140-44, 444 N.W.2d 610 (1989), cert. denied, 498 U.S. 881, 111 S.Ct. 216, 112 L.Ed.2d 176 (1990); State v. Goodman, 298 N.C. 1, 24-26, 257 S.E.2d 569 (1979); State v. Pritchett, 621 S.W.2d 127, 137-39 (Tenn. 1981); State v. Wood, 648 P.2d 71, 85-86 (Utah 1981), cert. denied, 459 U.S. 988, 103 S.Ct. 341, 74 L.Ed.2d 383 (1982); Smith v. Commonwealth, 219 Va. 455, 477-78, 248 S.E.2d 135 (1978), cert. denied, 441 U.S. 967, 99 S.Ct. 2419, 60 L.Ed.2d 1074 (1979); but see People v. Superior Court of Santa Clara County, 31 Cal.3d 797, 801-802, 647 P.2d 76, 183 Cal.Rptr. 800 (1982). Appropriately limited by a suitable instruction, 53a-46a(h)(4) does not violate the defendant's right to due process under the state constitution.

The defendant's final claim is that the unanimity requirement that we construed to be part of our death penalty statute in State v. Daniels, supra, 207 Conn. 388-89, undermines his right to due process. As we noted in our discussion of the defendant's parallel claim under the federal constitution, we disagree with the premise that underlies this contention. See part II A 2. Nothing in the statute or in our decision in Daniels limits the ability of any juror to consider any fact offered in support of mitigation. In order to arrive at a decision that a mitigating factor has been proven, the jurors need not agree on the same mitigating factor. All that unanimity requires is that each juror must be persuaded of the existence of a mitigating factor. Due process requires no less and no more. As a matter of federal law see McKoy v. North Carolina, supra, 494 U.S. 433; and as a matter of state law see People v. Rodriguez, 794 P.2d 965, 980-82 (Colo. 1990), cert. denied, 498 U.S. 1055, 111 S.Ct. 770, 112 L.Ed.2d 789 (1991), and State v. Smith, 781 S.W.2d 761, 767-68 (Mo. 1989), vacated, 495 U.S. 916, 110 S.Ct. 1944, 109 L.Ed.2d 306, aff'd on remand, 790 S.W.2d 241 (Mo. 1990).

We therefore conclude that the Connecticut death penalty statutes are not unconstitutional on their face on any of the grounds alleged by the defendant, either under the United States constitution or under the Connecticut constitution. The statutes authorize the death penalty only in defined circumstances that impose a heavy burden on the state to justify the death penalty and that permit the defendant wide latitude to persuade the sentencer to the contrary. The statutes therefore do not violate the prohibition of cruel and unusual punishment and do not infringe upon the defendant's rights to due process.

III

VALIDITY OF THE SENTENCING HEARING IN THIS CASE

The defendant challenges the validity of the death sentences imposed upon him on the ground that the sentencing hearing in this case failed to comply with the requirements of 53a-46a. As a matter of evidentiary sufficiency, he maintains that the trial court improperly: (1) failed to set aside the jury's finding that the state had adduced sufficient evidence to prove an aggravating factor beyond a reasonable doubt; and (2) failed to set aside the jury's finding of insufficient evidence to prove a mitigating factor by a fair preponderance of the evidence. As a matter of evidentiary rulings, he maintains that the trial court improperly: (1) excluded mitigating evidence; and (2) permitted irrelevant or prejudicial evidence to be presented to prove the aggravating factor. As a matter of jury instructions, he maintains that the trial court improperly charged the jury with regard to: (1) the definition of the aggravating factor that the crime had been committed "in an especially heinous, cruel or depraved manner"; (2) the two witness requirement of 54-83; (3) reasonable doubt; (4) permissible inferences from missing witnesses; and (5) statutory and nonstatutory mitigating factors. Furthermore, the defendant maintains that the trial court improperly: (1) permitted prejudicial commentary by the prosecuting attorney; (2) denied the defendant's motion for mistrial; (3) failed to merge two capital convictions for one victim into one capital felony conviction; (4) failed to sever the sentencing hearing into three separate hearings; (5) denied the defendant's motion for surrebuttal on the issue of mitigation; and (6) rejected the defendant's claim of juror prejudice.

We conclude that an entirely new sentencing hearing must be held. Although there was sufficient evidence to sustain the jury's finding that the state had proved an aggravating factor beyond a reasonable doubt, the jury's finding of "no mitigating factor" cannot stand because of the trial court's evidentiary and instructional rulings that did not comply with the statutory requirements of 53a-46a.

A

SUFFICIENCY OF THE EVIDENCE

In our assessment of the validity of the penalty phase proceedings that were in fact held in this case, the first issue is the sufficiency of the evidence upon which the trial court relied in imposing the death penalty upon the defendant. General Statutes 53a-46b(b)(2). Under 53a-46a(f), a court may sentence a person to death only if the trier of fact has found that the state has established the existence of an aggravating factor beyond a reasonable doubt and that the defendant has failed to establish a mitigating factor by a preponderance of the evidence. State v. Daniels, supra, 207 Conn. 384-85. In these cases, the jury found that the state had met its burden of proof that the defendant, as charged, had committed the offenses "in an especially heinous, cruel or depraved manner." General Statutes 53a-46a(h)(4). If, as the defendant contends, the state failed to prove this aggravating factor, or he proved a mitigating factor, principles of double jeopardy would require us to remand this case to the trial court with direction to impose life sentences upon the defendant. State v. Daniels, supra, 397-99.

The defendant urges us to employ a heightened standard of review in our determination, on appeal, of whether the state has presented sufficient evidence to prove the existence of an aggravating factor. He maintains that 53a-46b(b)(2) confers upon this court discretionary authority comparable to that vested in the sentence review division by General Statutes 51-195. See State v. Nardini, 187 Conn. 109, 118-22, 445 A.2d 304 (1982); Consiglio v. Warden, 153 Conn. 673, 676-77, 220 A.2d 269 (1966). We disagree. Section 53a-46b(b)(2) requires only a determination of whether "the evidence fails to support the finding of an aggravating factor specified in subsection (h) of section 53a-46a . . . ." That language gives no indication that the legislature intended a fundamental alteration in the standard of review that generally governs a criminal defendant's challenge of the sufficiency of the evidence of his guilt at trial. See State v. Francis, 228 Conn. 118, 127, 635 A.2d 762 (1993); State v. Joyner, supra, 225 Conn. 455. Nonetheless, because of the seriousness of any death penalty determination, we will subject a finding of an aggravating factor to the same independent and scrupulous examination of the entire record that we employ in our review of constitutional fact-finding, such as the voluntariness of a confession; State v. Medina, 228 Conn. 281, 294, 636 A.2d 351 (1994); State v. Smith, 200 Conn. 465, 478, 512 A.2d 189 (1986); or the seizure of a defendant. State v. Greenfield, 228 Conn. 62, 68-69, 634 A.2d 879 (1993); State v. Northrop, 213 Conn. 405, 414, 568 A.2d 439 (1990).

1

In support of its allegation that it proved that the defendant had acted "in an especially heinous, cruel or depraved manner"; General Statutes 53a-46a(h)(4); the state makes two arguments. It contends that the defendant acted in an especially heinous or depraved manner because of the defendant's state of mind when he kidnapped, raped and strangled his victims. Furthermore, the state contends that the defendant acted in an especially cruel manner because of the physical and mental pain that he intentionally inflicted on each victim.

Before we review the evidence adduced by the state, we must clarify the standard by which it is to be measured. As we acknowledged in State v. Breton, supra, 212 Conn. 265, the phrase "in an especially heinous, cruel or depraved manner" contains an arguably subjective standard that runs the risk of being unconstitutionally vague. To avoid constitutional jeopardy for this aggravating factor, we adopted a limiting construction of 53a-46a(h)(4). Focusing on the meaning of "especially cruel," we concluded that an acceptable core construction of this term "must include the intentional infliction of extreme pain or torture above and beyond that necessarily accompanying the underlying killing." Id., 270.

Our decision in Breton did not address two further issues concerning the proper construction of 53a-46a (h)(4). First, does the "extreme pain or torture" that is at the core of "especially cruel" include the infliction of psychological anguish as well as physical pain? Second, does 53a-46a(h)(4) envisage three separate aggravating factors, so that an independent core meaning must be assigned to "depraved" and "heinous," or are these terms to be read conjointly to describe a single aggravating factor?

The defendant argues in this appeal that "extreme pain or torture" cannot be psychological. We disagree. A defendant cannot intentionally engage in conduct that inflicts extreme psychological trauma and then claim that his victims' mental distress was unintended or unforeseeable. Breton did not exclude mental anguish from actionable "extreme pain or torture" and we decline to do so now. See Walton v. Arizona, supra, 497 U.S. 646-47. No different analysis is required as a matter of state constitutional law.

The state argues that 53a-46a(h)(4) permits the state to prove an aggravating factor premised on "especially heinous or depraved" that focuses solely on the defendant's state of mind when he kidnapped, raped and strangled his victims. We are not persuaded that we can discern a core meaning for these individual terms solely as a mental state that will shield them from unconstitutional vagueness. More important, however, as a matter of statutory construction, we are not persuaded that 53a-46a(h)(4) was intended to encompass more than one unitary aggravating factor. In our view, the terms "heinous or depraved" address the defendant's state of mind in intentionally inflicting on his victim extreme pain or torture above and beyond that necessarily accompanying the underlying killing. So construed, 53a-46(h)(4) passes constitutional muster under the United States constitution; see Proffitt v. Florida, supra, 428 U.S. 255-56; and under our state constitution.

A construction of 53a-46a(h)(4) as a unitary aggravating factor that focuses on the infliction of extreme pain or psychological or physical torture on the victim finds support in the structure of 53a-46a(h) and in accepted principles of statutory analysis. Structurally, each of the separate clauses of subsection (h) defines a discrete set of aggravating circumstances. Analytically, under the doctrine of noscitur a sociis, "[i]f two or more words are grouped together, it is possible to ascertain the meaning of a particular word by reference to its relationship with other associated words and phrases . . . ." State v. Indrisano, 228 Conn. 795, 811, 640 A.2d 986 (1994); Staples v. Palten, 214 Conn. 195, 199-200, 571 A.2d 97 (1990); State v. Roque, 190 Conn. 143, 152-53, 460 A.2d 26 (1983).

In Indrisano, we relied upon the doctrine of noscitur a sociis to find limiting constructions of our disorderly conduct statute; General Statutes 53a-182(a); to save that statute from unconstitutional vagueness. We construed the language "[e]ngages in fighting or in violent, tumultuous or threatening behavior" as a prohibition of physical fighting and physically violent, threatening or tumultuous behavior. State v. Indrisano, supra, 228 Conn. 812. We held that the statutory phrase "`by offensive or disorderly conduct'" was to be read as a unitary phrase in which each adjective complements the meaning of the other. Id., 817-18. Our application of this rule of statutory construction was consistent with earlier decisions holding that, in our robbery statute; General Statutes 53a-133; "the three words `taking,' `obtaining,' and `withholding' are inseparable." State v. Pelletier, 209 Conn. 564, 576, 552 A.2d 805 (1989); State v. John, 210 Conn. 652, 688-89, 557 A.2d 93, cert. denied, 493 U.S. 824, 110 S.Ct. 84, 107 L.Ed.2d 50 (1989).

In a review of the sufficiency of the evidence to support the jury's finding of an aggravating factor under 53a-46a(h)(4), we hold, therefore, that the focus must be on whether the state has proved, beyond a reasonable doubt, that the defendant engaged in intentional conduct that inflicted extreme physical or psychological pain or torture on each of his victims above and beyond that necessarily accompanying the underlying killing. Evidence of the defendant's callousness or indifference to his victims' suffering would substantiate such a finding, but it would not suffice without some showing of the infliction of extreme pain, suffering or torture on the victims. We conclude that the state has met its evidentiary burden in this case.

The jury reasonably could have found, for each of the defendant's four victims in the circumstances of these cases, that their manual strangulation by the defendant was an especially cruel way of inflicting death. In the cases of Wendy B. and Robyn S., the defendant's cruelty was exacerbated when their strangulation was prolonged by the cramping of the defendant's hands, which caused him to stop before resuming the strangulation. For each of these young and emotionally vulnerable victims, moreover, the jury reasonably could have found that the conjoining of the kidnapping with the strangulation would have produced extreme anxiety, fear and uncertainty as to her ultimate fate. See State v. Havican, 213 Conn. 593, 599-600, 569 A.2d 1089 (1990); Fairbanks v. State, 143 Conn. 653, 660, 124 A.2d 893 (1956). Except in the case of Leslie S., the jury reasonably could have inferred that the victims' terror would have been increased by the defendant's sexual assaults upon them. For Leslie S., the jury reasonably could have found that she would have been terrified by sitting in the defendant's car, bound hand and foot, and coming to understand that her best friend, April B., was being sexually abused and then killed. Finally, the jury reasonably could have found that the defendant's lack of remorse substantiated a finding that his infliction of suffering upon his victims was intentional. Such findings have probative force even though they are based on inferences rather than on direct evidence; State v. Medina, supra, 228 Conn. 309; State v. Greenfield, supra, 228 Conn. 76-77;. and even though the jury might have drawn contrary inferences. State v. Francis, supra, 228 Conn. 127; State v. Grant, 219 Conn. 596, 604, 594 A.2d 459 (1991).

We reject the defendant's contention that the evidence adduced by the state does not prove that his conduct was "especially heinous, cruel or depraved," as a matter of law, because his conduct did not go beyond that which is necessarily encompassed by the capital felonies of which he was convicted. The defendant focuses on the fact that the use or the threat of use of force is a predicate element of the kidnapping and of the sexual assault aspects of these capital felonies. He maintains, therefore, that in using force on his victims, and in threatening them with the use of force, he was not inflicting "extreme pain or torture above and beyond that necessarily accompanying the underlying killing."

The defendant cannot prevail on this argument because the state presented ample evidence at the penalty hearing to show that, for each capital felony count, there were aggravating circumstances beyond the elements of the crimes charged. With respect to Wendy B. and Robyn S., the jury received evidence about the effect of the kidnapping as an aggravating factor for the capital felony count predicated on a sexual assault, and evidence about the effect of the sexual assault as an aggravating factor for the capital felony count predicated on a continuing kidnapping. On this record, the jury reasonably could have found an aggravating factor for each of these capital felony counts because of the proof of an added element from the other felony count. See State v. Murphy, 65 Ohio St.3d 554, 578, 605 N.E.2d 884 (1992). With respect to April B., her sexual assault by the defendant was likewise an aggravating factor above and beyond the kidnapping and the murder that were elements in the capital felony as charged. With respect to Leslie S., an aggravating factor of special cruelty was the exacerbated psychological anguish inflicted upon her by her own bondage and her fear for the fate of her best friend.

Even with the heightened appellate scrutiny appropriate for a death penalty case, the defendant's challenge to the sufficiency of the evidence of aggravating circumstances must be reviewed, in the final analysis, by considering the evidence presented at the defendant's penalty hearing in the light most favorable to sustaining the facts impliedly found by the jury. On the basis of these implied factual findings about the defendant's conduct and its likely impact on the victims in these cases, we conclude that the jury reasonably could have concluded that the cumulative effect of the evidence established beyond a reasonable doubt the existence of an aggravating factor as defined by 53a-46a (h)(4) for each of the six capital felony counts with which the defendant was charged. See State v. Francis, supra, 228 Conn. 127; State v. Joyner, supra, 225 Conn. 455.

2

The defendant also maintains that he presented sufficient evidence of statutory and nonstatutory mitigating factors to meet his burden of proving mitigation by a preponderance of the evidence. Although the jury found to the contrary, he maintains that an independent review of the evidence of mitigation by this court will establish that the trial court improperly imposed the death penalty upon him. This claim focuses on the testimony of the defendant's three psychiatric experts that the defendant's mental impairment, stemming from his disturbed family background and aberrant sexual development, was a mitigating factor in his crimes.

The state responds that such appellate review is unauthorized as a matter of law and unwarranted in the circumstances of this case. We need not decide today the legal question of whether the specific authority to review a finding of an aggravating factor; General Statutes 53a-46b(b)(2); necessarily implies a legislative intent to preclude appellate review of a finding that there is no mitigating factor. For this appeal, it suffices to recognize that the defendant's right to present evidence by way of mitigation does not compel a jury to find that evidence credible. Even without countervailing expert evidence of its own, the state can weaken the force of the defendant's presentation by cross-examination and by pointing to inconsistencies in the evidence. See State v. Medina, supra, 228 Conn. 309-10; State v. Steiger, 218 Conn. 349, 381, 590 A.2d 408 (1991); State v. Murphy, supra, 65 Ohio St.3d 569 -70. The defendant cannot prevail on this issue.

B

EVIDENTIARY ISSUES RELATING TO THE PENALTY HEARING

The defendant has raised numerous evidentiary claims relating to the penalty phase of his trial. We conclude that improper evidentiary rulings by the trial court substantially limited the defendant's right to present mitigating evidence and require a new sentencing hearing.

1

The defendant first asserts that, in violation of General Statutes 53a-46a(c), the trial court improperly excluded evidence relevant to mitigation. Although the statute expressly permits the presentation of "[a]ny information relevant to any mitigating factor," the trial court precluded the defendant from submitting to the jury: (a) a letter written by Robert Miller, a court appointed psychiatric expert who had evaluated the defendant for the state, which reflected the fact that he had changed his position about the mitigating role of the defendant's psychopathology; and (b) a report by Miller, which reflected his corroboration of the diagnosis of the defendant contained in the reports of defense psychiatric experts.

On appeal, the state contends that the proffered evidence was properly excluded as not "relevant to any mitigating factor" because it was unauthenticated hearsay and unreliable. Unless the statute impliedly authorizes a trial court to exclude unreliable evidence, the state maintains that the statute would infringe on constitutional principles of separation of powers.

We agree with the defendant that the mandate of 53a-46a(c) required the trial court to admit the mitigating evidence that he proffered in this case. The statute plainly provides that, in a penalty hearing conducted pursuant to 53a-46a, "[a]ny information relevant to any mitigating factor may be presented by either the state or the defendant, regardless of its admissibility under the rules governing admission of evidence in trials of criminal matters . . . ." (Emphasis added.) On its face, this language authorizes a judge presiding over a penalty hearing to exclude mitigating evidence only on the basis of a lack of relevancy.

"It is fundamental that statutory construction requires us to ascertain the intent of the legislature and to construe the statute in a manner that effectuates that intent. . . . All Brand Importers, Inc. v. Department of Liquor Control, 213 Conn. 184, 194, 567 A.2d 1156 (1989). Where the language of a statute is clear and unambiguous, reference to its history and purpose is unnecessary. Winslow v. Lewis-Shepard, Inc., 216 Conn. 533, 538, 582 A.2d 1174 (1990). It is the duty of the court to interpret statutes as they are written . . . and not by construction read into statutes provisions which are not clearly stated." (Citations omitted; internal quotation marks omitted.) State v. Johnson, 227 Conn. 534, 541-42, 630 A.2d 1059 (1993); Forsyth v. Rowe, 226 Conn. 818, 828, 629 A.2d 379 (1993); State v. Dupree, 196 Conn. 655, 660, 495 A.2d 691, cert. denied, 474 U.S. 951, 106 S.Ct. 318, 88 L.Ed.2d 301 (1985). Accordingly, we decline the state's invitation to read into the statute a foundational requirement of reliability for admissibility of mitigating evidence at a capital penalty phase hearing. See also C. Tait J. La Plante, Connecticut Evidence (2d Ed. 1988) 3.5.8(b) (distinguishing relevancy, competency and authenticity of evidence).

We disagree with the state's contention that a literal reading of 53a-46a(c) puts the statute at constitutional risk of violating applicable principles of separation of powers. See Moscone v. Manson, 185 Conn. 124, 128, 440 A.2d 848 (1981). "A statute violates the constitutional mandate for a separate judicial magistracy only if it represents an effort by the legislature to exercise a power which lies exclusively under the control of the courts. . . . Bartholomew v. Schweizer, [ 217 Conn. 671, 676, 587 A.2d 1014 (1991)]." (Citations omitted; internal quotation marks omitted.) State v. Campbell, 224 Conn. 168, 177, 617 A.2d 889 (1992), cert. denied, ___ U.S. ___, 113 S.Ct. 2365, 124 L.Ed.2d 271 (1993). "[T]he rules of evidence . . . have never in this state been regarded as exclusively within the judicial domain." State v. James, 211 Conn. 555, 560, 560 A.2d 426 (1989).

The state nonetheless argues that a construction of 53a-46a(c) that limits the trial court's role, with respect to mitigating evidence, to an assessment of relevance "defies logic [and] impairs the essential function of the judiciary." We disagree. Although we have "held unconstitutional statutes modifying the rules of evidence in such manner as to defy logic," we have not done so in reliance "upon any grant of exclusive authority to the courts under article second to promulgate rules of evidence but upon other constitutional principles, such as due process and equal protection." State v. James, supra, 211 Conn. 561-62. The exclusion of considerations of reliability does not per se undermine a trial court's authority to preserve the integrity of the proceeding.

The broad sweep of 53a-46a(c) reflects a balance struck by the legislature between a defendant's eighth amendment right to receive individualized consideration when faced with the death penalty; see Lockett v. Ohio, supra, 438 U.S. 606; and a trial court's need to exercise appropriate control over courtroom proceedings. The state's rhetoric does not specify in what particular manner this balance "significantly interferes with the orderly functioning of the Superior Court's judicial role." State v. Campbell, supra, 224 Conn. 178. We are persuaded that a relevance standard retains sufficient discretion for the court to enable it to exercise proper control over the admissibility of evidence. State v. Pollitt, 205 Conn. 61, 91, 530 A.2d 155 (1987).

The state argues, in the alternative, that, read as a whole, 53a-46a(c) must be construed to allow only "relevant evidence whose reliability can be tested before the jury." This argument is premised on additional language in 53a-46a(c) permitting the "[t]he state . . . to rebut any information received at the hearing and [giving the state] fair opportunity to present argument as to the adequacy of the information to establish . . . any mitigating . . . factor." Acceptance of the state's position would make the test for the defendant's right to present mitigating evidence turn on the state's right to undertake an effective rebuttal by way of cross-examination or otherwise. As the defendant correctly observes, such a limitation on the admissibility of mitigating information in capital penalty hearings would be more restrictive than that generally governing rules of evidence. We therefore reject the state's construction. The language quoted by the state creates a temporal opportunity for the state to rebut mitigating evidence and permits argument on the weight of such evidence. It does not, however, limit the scope of the mitigating information that the defendant may present to the trier at the penalty phase hearing.

Turning now to the specific claims of error, we conclude that the trial court improperly excluded both the letter and report of Miller, because both were relevant to mitigation. General Statutes 53a-46a(c). The concept of relevancy is well established in our criminal jurisprudence. "[R]elevant evidence is evidence that has a logical tendency to aid the trier in the determination of an issue. State v. McClendon, 199 Conn. 5, 8-9, 505 A.2d 685 (1986). Evidence is irrelevant .if there is `such a want of open and visible connection between the evidentiary and principal facts that, all things considered, the former is not worthy or safe to be admitted in proof of the latter.' State v. Kelly, 77 Conn. 266, 269, 58 A. 705 (1904)." State v. Jeffrey, 220 Conn. 698, 704, 601 A.2d 993 (1991), cert. denied, ___ U.S. ___, 112 S.Ct. 3041, 120 L.Ed.2d 909 (1992).

The letter and report in question were produced by a psychiatrist appointed by the court to evaluate the defendant for the state. The letter reflects not only Miller's change of position in favor of "psychopathology playing a sufficient role in [the] defendant's behavior to mitigate the type of penalty," but also Miller's extreme reluctance to make himself available to testify. Miller's report corroborated the defense psychiatric experts' opinions that the defendant suffered from sexual sadism. Not only did this evidence bear directly on the question of whether, at the time of the offense, the defendant's "mental capacity was significantly impaired" so as to warrant mitigation; General Statutes 53a-46a(g)(2); but it could have appeared more objective and worthy of belief than evidence adduced by the defendant from his own expert witnesses. See Brennan v. State, 766 P.2d 1385, 1386-87 (Okla.Cr. 1988) (harmful error to exclude letter from state's psychiatric expert). The fact that it was the defendant's burden to prove mitigation by a preponderance of the evidence persuades us that the improper exclusion of this unique evidence was more likely than not to have affected the result of the sentencing hearing. State v. Tatum, 219 Conn. 721, 738, 595 A.2d 322 (1991); State v. Jones, 205 Conn. 723, 732, 535 A.2d 808 (1988). Accordingly, we conclude that exclusion of the report and letter violated 53a-46a(c) and was harmful. A new penalty hearing is therefore required.

2

The defendant also claims that the trial court improperly allowed the state to introduce irrelevant or prejudicial evidence to prove aggravation and to rebut mitigation. Specifically, the defendant contends that it was harmful error to permit the state to introduce: (a) testimony by a state's expert about rape trauma syndrome; (b) testimony of Warden Orszak regarding good time credits, minimum security institutions, and the possibility of pardon, and testimony of Fred Berlin, a psychiatrist, regarding the defendant's potential dangerousness if ever released; and (c) evidence about the victims including testimony on their physical characteristics and personalities and photographs of their appearance both before and after their murders. We address these claims only to the extent that they are likely to arise again at a new sentencing hearing.

The admissibility of evidence in a capital sentencing hearing is governed by 53a-46a(c). In the absence of applicable statutory mandates, evidentiary rulings are within the sound discretion of the trial court and are reversible only "if there is an abuse of discretion and a showing of substantial prejudice or injustice to the defendant. State v. Alvarez, 216 Conn. 301, 306, 579 A.2d 515 (1990)." State v. Colton, 227 Conn. 231, 260, 630 A.2d 577 (1993). Because a new hearing is required, however, we need not engage in harmless error analysis with respect to these claims.

The defendant's first challenge to the evidence that was admitted over his objection is to the state's presentation of expert testimony regarding rape trauma syndrome. The state's expert testified that every victim of sexual assault, to some degree, experiences "feelings of helplessness, powerlessness, fear, panic, horror; feelings of personal intrusion, violation; feelings of being entrapped . . . a sense of not being able to be rescued, a feeling of isolation, abandonment," and that these emotions exist from just before the assault until shortly thereafter. The defendant asserts that this evidence was not relevant to aggravation, because it described the feelings experienced by every rape victim, and did not serve to distinguish these particular rapes as "heinous, cruel or depraved." General Statutes 56a-46a(h)(4) [ 53a-46a(h)(4)].

The state does not dispute the generic nature of the expert testimony but argues that the testimony was relevant to show aggravation for the capital felony counts that were based on kidnapping and murder. We agree with the state. A sexual assault that occurs during the course of a kidnapping that results in murder is relevant evidence for the jury to consider in determining whether the state has proven aggravation of that kidnap/murder. The additional fact of a sexual assault is relevant irrespective of whether the sexual assault, in and of itself, was especially cruel. The trial court properly admitted this testimony over the defendant's objection on grounds of relevance.

The defendant's second claim is that the court improperly permitted the state to cross-examine two of the defendant's witnesses to rebut his evidence on mitigation. In the defendant's presentation to prove mitigation, Warden Orszak testified for the purpose of showing "an inmate's ability to do useful and productive work while incarcerated." Over the defendant's objections, the state cross-examined Orszak regarding good time credits, minimum security institutions, and the possibility of pardon. Later, again over the defendant's objections, the state cross-examined Berlin, a defense psychiatric expert, on whether the defendant would be dangerous if released in ten years. The defendant asserts that, because such cross-examination related to future dangerousness, it was not relevant to rebut the defendant's case for mitigation. The state argues to the contrary that this evidence rebutted an assumption underlying the defendant's claim that he would be a good prisoner by contending that the defendant would not actually remain a prisoner. To the extent that these issues may arise at the sentencing rehearing, the court should be guided by the general rule limiting the scope of cross-examination to the matters elicited on direct examination. State v. McCarthy, 197 Conn. 247, 260, 496 A.2d 513 (1985); see People v. Garcia, 97 Ill.2d 58, 87-88, 454 N.E.2d 274 (1983), cert. denied, 467 U.S. 1260, 104 S.Ct. 3555, 82 L.Ed.2d 856 (1984).

The defendant finally asserts that the trial court improperly admitted, as evidence of aggravation, testimony and exhibits concerning the physical characteristics and personalities of the victims, all of which the defendant claims to have been irrelevant and highly prejudicial. The evidence at issue consisted of testimony describing the victims, studio-type photographic portraits of how they looked before the murders, and postmortem photographs showing their bodies after the murders. The state proffered this evidence to enable it to meet its burden of proving the aggravating factor that the defendant's crimes were "especially cruel" under 53a-46a(h)(4). To meet this burden, the state must show "the intentional infliction of extreme pain or torture above and beyond that necessarily accompanying the underlying killing." State v. Breton, supra, 212 Conn. 270. On appeal, we must determine whether the trial court abused its discretion in admitting this evidence as more probative than prejudicial. State v. Woodson, 227 Conn. 1, 17, 629 A.2d 386 (1993).

The state introduced testimony briefly describing each of the victims as a petite young teenager who was a caring, sensitive and trusting person. In addition, the state introduced exhibits consisting of photographs of the victims before and after abduction, including those of the severely decomposed bodies of Leslie S. and April B. The trial court admitted all this evidence, impliedly finding that it was more probative than prejudicial. The evidence at issue demonstrated a gross disparity in size between the defendant and the victims, and corroborated evidence relating to the manner in which the crimes had occurred. The testimony regarding the age and emotional makeup of these girls reflected a level of maturity that could elevate the degree of terror a jury might believe they would have experienced during the assaults.

The defendant does not take issue with the standard of appellate review that governs discretionary evidentiary rulings of the trial court. He nonetheless maintains that, in capital sentencing proceedings, there should be heightened concern for potential prejudice, especially from inflammatory photographs, citing State v. Pitts, 116 N.J. 580, 638-39, 562 A.2d 1320 (1989) (cautioning courts to exercise discretion in admitting photographs of crime victims with careful consideration of state's burden of proof, other evidence adduced by state, and rules of evidence). We urge such careful consideration upon the trial court at the sentencing rehearing. See State v. Haskins, 188 Conn. 432, 453, 450 A.2d 828 (1982). We note, however, that even gruesome photographs are admissible if they would prove or disprove a material fact in issue, or illuminate a material inquiry. Id., 452.

C

INSTRUCTIONAL ISSUES RELATING TO THE PENALTY HEARING

Because we have already decided that a new sentencing hearing must be held to determine whether the death penalty should be imposed on the defendant, we will address the defendant's numerous challenges to the trial court's penalty phase jury instructions only with the view to giving guidance for the conduct of the new sentencing hearing. With regard to aggravation, the defendant maintains that the trial court improperly charged the jury on: (1) the definition of the aggravating factor contained in 53a-46a(h)(4) requiring a showing that the crime was committed "in an especially heinous, cruel or depraved manner"; (2) the two witness requirement of 54-83; and (3) reasonable doubt. With regard to mitigation, the defendant maintains that the trial court improperly charged the jury on: (1) permissible inferences from missing witnesses; and (2) statutory and non statutory mitigating factors.

1

None of the issues raised by the defendant with regard to the trial court's instructions on aggravation warrants extended consideration in the present posture of this case. Some have already been dealt with previously in this opinion.

We have described a constitutionally appropriate narrowing of the definition of "especially heinous, cruel or depraved" in the discussion of the state's proof of the aggravating factor in part III A. That discussion should suffice to guide the trial court in the future.

We have discussed the scope of the instructions required by the two witness rule of 54-83 in part I dealing with the defendant's guilt. We agree, however, with the state that 54-83 applies only to the guilt phase and not to the penalty phase of a capital felony trial. Section 54-83 provides: "No person may be convicted of any crime punishable by death without the testimony of at least two witnesses, or that which is equivalent thereto." (Emphasis added.) Unless the context indicates the contrary, the word "conviction" means "a finding of the party guilty by verdict or plea of guilty, and not to a sentence in addition." Quintard v. Knoedler, 53 Conn. 485, 488, 2 A. 752 (1885). In the prefatory language of 53a-46a(b), our death penalty statute expressly incorporates the traditional distinction between the processes of convicting and sentencing. The statute reads: "For the purpose of determining the sentence to be imposed when a defendant is convicted of or pleads guilty to a capital felony . . . ." (Emphasis added.) We assume that the legislature knew and intended to adopt the longstanding judicial construction of the word "conviction" when it revised the death penalty statutes in 1973, and revised 54-83 in 1980. State v. Dabkowski, 199 Conn. 193, 201, 506 A.2d 118 (1986). Construing the statute as it is written; State v. Johnson, 227 Conn. 534, 541-42, 630 A.2d 1059 (1993); Forsyth v. Rowe, 226 Conn. 818, 828, 629 A.2d 379 (1993); State v. Dupree, 196 Conn. 655, 660, 495 A.2d 691, cert. denied, 474 U.S. 951, 106 S.Ct. 318, 88 L.Ed.2d 301 (1985); we conclude that 54-83 has no application to a capital sentencing hearing.

The defendant also challenges the trial court's penalty phase instruction on reasonable doubt. This instruction was identical to that given during the guilt phase. We have concluded that its wording did not amount to constitutional error. See part I C 3 of this opinion. Because the defendant did not preserve this claim at trial, it warrants no further discussion.

2

With regard to mitigation, the defendant contends that the trial court improperly charged the jury on: (a) the permissible inferences to be drawn from the defendant's failure to call his parents to testify; and (b) nonstatutory and statutory mitigating factors. Some of these contentions warrant serious consideration at the new sentencing hearing.

The defendant first asserts that the trial court improperly gave a Secondino charge instructing the jury that it might draw inferences unfavorable to the defendant because he failed to call his parents at the penalty phase hearing. The defendant argues that he presented evidence of his parents' mistreatment of him as a child as a contributing cause of his psychological problems and that, consequently, his parents were hostile witnesses and not ones the defendant would naturally call. See State v. Grant, 221 Conn. 93, 104-107, 602 A.2d 581 (1992); D'Amico v. Manson, 193 Conn. 144, 153, 476 A.2d 543 (1984); State v. DePaola, 5 N.J. 1, 19-20, 73 A.2d 564 (1950). The defendant also argues that his parents were cooperating with the state during the trial, and were equally available to the state, making a Secondino inference improper in these circumstances. In light of these uncontroverted facts, the trial court at the penalty phase rehearing should reconsider the propriety of a Secondino instruction.

The defendant also challenges the manner in which the trial court instructed the jury on the definition of nonstatutory mitigating factors. The defendant maintains that the trial court improperly charged the jury on 53a-46a(d) and inadequately charged the jury on other aspects of the evidence relating to mitigation. Finally, the defendant argues that the trial court improperly explained the requirement for unanimity in their findings. Bearing in mind that we review instructions to the jury in their entirety, we will address only those claims that raise issues that are likely to recur at a rehearing.

Although the crimes were committed in 1983 and 1984, the court utilized the language of Public Acts 1985, No. 85-366 1(d), now codified at General Statutes 53a-46a(d) (subsection [d]). The defendant contends: (i) that subsection (d) cannot be applied in his case to nonstatutory mitigating factors without violating Connecticut law and the prohibition against ex post facto laws contained in article one, 10, of the United States constitution; and (ii) that subsection (d) cannot constitutionally be applied in any case because it calls for an internal balancing of mitigants against aggravants that is unreviewable, or standardless and arbitrary. We disagree with both of these contentions.

"The rules of law that underlie the defendant's [first] claim under the United States constitution are well established. The prohibition of ex post facto laws forbids the enactment of `any law "which imposes a punishment for an act which was not punishable at the time it was committed; or imposes additional punishment to that then prescribed." Cummings v. Missouri, 4 Wall. 277, 325-26, 18 L.Ed. 356 (1867).' Weaver v. Graham, 450 U.S. 24, 28, 101 S.Ct. 960, 67 L.Ed.2d 17 (1981); see also W. LaFave A. Scott, Criminal Law (1972) 12; 2 R. Rotunda, J. Nowak J. Young, Treatise on Constitutional Law: Substance and Procedure (1986) 15.9(b); L. Tribe, American Constitutional Law (1978) 10-2, 10-3. Under the applicable federal cases, `two critical elements must be present for a criminal or penal law to be ex post facto: it must be retrospective, that is, it must apply to events occurring before its enactment, and it must disadvantage the offender affected by it.' (Emphasis in original.) Weaver v. Graham, supra, 29." State v. Rollinson, 203 Conn. 641, 646, 526 A.2d 1283 (1987).

The law in Connecticut is also well established. "A statute `affecting substantial changes in the law' is not to be given a retrospective effect unless it clearly and unequivocally appears that such was the legislative intent." (Emphasis added.) State v. Paradise, 189 Conn. 346, 351, 456 A.2d 305 (1983). A procedural statute, however, will be applied retroactively without a legislative imperative to the contrary unless "considerations of good sense and justice dictate that it not be so applied." Id.

Accordingly, both under federal precedents and under the law of Connecticut, a statute may have retroactive effect if the legislature so intends and if the statute does not enact a substantive change in the law. The defendant does not challenge this general principle. He maintains, however, that subsection (d) adds "some sort of weighing or balancing process to our statutory scheme and [that this] places substantive limitations on the definition of a nonstatutory mitigating factor" and that the subsection therefore may not be applied retroactively. We disagree. Subsection (d) merely codifies the definition for mitigating factors utilized in capital cases prior to the enactment of Public Acts 1985, No. 85-366 1. See State v. Wood, Superior Court, judicial district of Hartford-New Britain at Hartford, Docket No. 48729 (sentencing hearing of July 24, 1984, utilizing jury instructions on mitigating factors indistinguishable from subsection [d]); Judiciary Hearing, April 1, 1985, pp. 1537-38 (testimony of Joseph Shortall, chief public defender); see also State v. Daniels, supra, 207 Conn. 386 n. 10.

Even if it is assumed, arguendo, that subsection (d) represents a change in the law, the change is at most procedural in nature. See State v. Almeda, 211 Conn. 441, 454, 560 A.2d 389 (1989). "[C]hanges in procedural law do not ordinarily give rise to violations of the prohibition against ex post facto laws in article one, 10 of the United States constitution. `[T]he constitutional provision was intended to secure substantial personal rights against arbitrary and oppressive legislation . . . and not to limit the legislative control of remedies and modes of procedure which do not affect matters of substance.' Beazell v. Ohio, 269 U.S. 167, 171, 46 S.Ct. 68, 70 L.Ed. 216 (1925); see also Collins v. Youngblood, 497 U.S. 37, 110 S.Ct. 2715, 111 L.Ed.2d 30 (1990)." Payne v. Fairfield Hills Hospital, 215 Conn. 675, 683, 578 A.2d 1025 (1990). Utilization of subsection (d) for the definition of a mitigating factor is therefore not improper.

We are equally unpersuaded by the defendant's argument that the jury should not have been charged on subsection (d) because that subsection unconstitutionally impairs the jury's opportunity to consider all the mitigating circumstances in his individual case. Under subsection (d), a fact is mitigating if "in fairness and mercy, [it] may be considered as tending either to extenuate or reduce the degree of his culpability or blame for the offense or to otherwise constitute a basis for a sentence less than death." In our view, this statutory language codifies the defendant's constitutional right to consideration of "`[those] compassionate or mitigating factors stemming from the diverse frailties of humankind.'" Caldwell v. Mississippi, supra, 472 U.S. 330; Eddings v. Oklahoma, supra, 455 U.S. 104; Lockett v. Ohio, supra, 438 U.S. 586. Furthermore, the trial court did not infringe upon the defendant's constitutional rights by instructing the jury to apply subsection (d) "considering all the facts and circumstances of the case." A jury that is entrusted with the awesome responsibility for deciding whether the death penalty should be imposed cannot be asked to find facts in a vacuum. The instructions as given did not preclude the jury from giving mitigating force to any fact, taken alone or taken in conjunction with any other facts presented.

The defendant makes an additional claim that the trial court's instruction on jury unanimity with respect to the existence of a mitigating factor was misleading. He argues that the trial court improperly failed to charge that unanimity was also required for a finding that no mitigating factor exists. Thus, the defendant argues, a jury hung on the existence of a mitigating factor may have believed that a verdict of "no mitigating factor" would be appropriate. We agree with the defendant that, at the rehearing, the jury should be given instructions that affirmatively and effectively convey this statutory requirement. Our holding in State v. Daniels, supra, 207 Conn. 374, which was decided subsequent to this sentencing hearing, is dispositive of this issue. A jury must be unanimous in its verdict that the defendant has not met his burden of proof on mitigation in order to satisfy the requirement of General Statutes 53a-46a (f) that "no mitigating factor exists." Id., 392, 394.

D

OTHER ISSUES RELATING TO THE PENALTY HEARING

Although we recognize that the defendant has raised numerous other issues concerning the conduct of his sentencing hearing, we are persuaded that they need not be addressed at this time. Furthermore, we need not undertake a review of the proportionality of the defendant's death sentences until there has been a proper determination by a sentencing jury that death sentences are warranted on any or all of the six capital felony counts of which the defendant stands convicted.

IV

SUMMARY

In summary, the defendant's convictions are affirmed in their entirety. The defendant kidnapped and killed four young girls, and sexually assaulted three of them, in a manner that was especially cruel, heinous or depraved. Imposition of the death penalty requires more, however. Even a defendant who has offered no persuasive legal excuse for his felonious conduct is entitled to have a sentencing jury consider extenuating circumstances that may explain his behavior and mitigate his moral culpability and may therefore counsel against the ultimate sanction of death. Because evidentiary rulings by the trial court impaired the defendant's ability to prove the existence of such mitigating factors, a new sentencing hearing must be held.