SULLIVAN, J.

On application by defendant after our decision herein. ( People v. Sanchez (1967) 65 Cal.2d 814 [56 Cal.Rptr. 648, 423 P.2d 800]), we granted his petition to recall the remittitur and vacated the decision wherein we had affirmed a judgment imposing the death penalty for a violation of Penal Code section 4500 (assault with deadly weapon by an inmate of a state prison undergoing a life sentence). We took such action because the appellate record on which we had reviewed the trial proceedings was incomplete in a respect which is critical to our determination as to whether defendant's extrajudicial confessions were voluntary.

We set forth the relevant facts. On April 23, 1965, defendant, an inmate at the State Prison at San Quentin undergoing a life sentence, was assigned to work under the supervision of Ralph Canning in the prison clothing factory. Canning and Chester Malin were civilian foremen in the factory; Stanford Raymond, not present on the day in question, was superintendent. No correctional officers were assigned to the factory area.

During the noon lunch period Canning and Malin were eating together in the superintendent's office enclosure within the factory. Defendant while on his way to lunch learned from another inmate that Canning intended to write a report about defendant's involvement in a sex complaint. Upset by this information and unable to eat his lunch, defendant returned to the clothing factory and entered the superintendent's office to discuss the matter with Canning in Malin's presence. In the ensuing discussion, defendant denied complicity in any sex offense, while Canning insisted that it was nevertheless his duty to report the matter. During the conversation defendant seemed "very irritated." Canning refused to discuss the matter further during the lunch hour and defendant eventually returned to his assigned station in the factory. Defendant testified that when he commenced work at his machine he could not concentrate on the job. He made a cup of coffee, but could not concentrate on drinking it. While returning his cup to its place in a drawer, he found a knife there.

About 2 p.m. Malin was asked by another inmate to inspect a machine which was claimed to be malfunctioning. After testing it for a few minutes, Malin looked up to notice inmates gathered in the vicinity of the superintendent's office. Upon investigation he found Canning's body lying face down on the office floor. Defendant was standing 35-40 feet away with blood on his clothing. An autopsy subsequently revealed that Canning had suffered 16 stab wounds in the area between his upper chest and upper thighs, varying in depth up to three inches. Two of the wounds punctured the heart, causing death.

Sergeant Beighley, a correctional officer, was called and arrived within a few minutes. The officer, upon seeing the body, asked, "Who did this?" Malin pointed to defendant, who was standing nearby. Beighley did not know defendant and had no recollection of having seen him before. He walked up to defendant who thereupon surrendered the knife. Beighley dropped it on the floor, placed his foot on it, and proceeded to search defendant for other weapons. He noticed that defendant's clothing was covered with blood. As he was searching defendant, Beighley inquired, "Why did you do it?" Defendant replied, "He was going to give me a sex beef." Beighley rejoined: "You have got something worse than a sex beef now."

The other inmates then left the clothing factory. As they were checked out, Malin observed each one but saw no one with blood on his clothing.

About 2:30 p.m. defendant was brought to the captain of the prison's correctional officers, Captain Hocker, to be interrogated. The latter advised defendant that he had a right to remain silent and not answer any questions, that he had a right to an attorney if he so desired, and that anything he said could be used against him. Defendant nevertheless chose to tell Captain Hocker what had happened. He stated that some time after his first talk with Canning he armed himself with a weapon and again attempted, unsuccessfully, to discuss the matter of the report Canning proposed to make. He then stated that he commenced to stab his victim. The foregoing conversation was not recorded.

Between 3 and 3:30 p.m. a deputy district attorney accompanied by a stenographic reporter interrogated defendant. Upon being advised again of his constitutional rights, defendant requested the assistance of counsel, and an unsuccessful attempt was made to obtain one.

On the following day Captain Hocker and a Lieutenant Moody approached defendant and advised him of his rights to remain silent and to an attorney and cautioned that anything he said could be used against him. Defendant did not request an attorney and made statements at this interrogation which are consistent with those he made earlier in Captain Hocker's office.

Defendant took the stand to testify in his own behalf. He stated that after seeing the knife in the drawer as he was returning his coffee cup he blacked out and that he remembered nothing until he regained consciousness in the adjustment center shortly after his first interview with Captain Hocker. He testified further that he had a similar experience in 1958 when he assaulted an inmate. He was impeached to some extent, however, when he admitted on cross-examination that during the trial for the earlier assault he had described that attack in detail and when an investigating officer testified that defendant had related details of the prior attack to him soon after it occurred.

Defendant contends on appeal (1) that there is insufficient evidence to establish that he acted with malice aforethought; (2) that he was mentally incapable of malicious conduct; (3) that the admission in evidence of his statement made to Sergeant Beighley constitutes reversible error under the rules announced in Escobedo v. Illinois (1964) 378 U.S. 478 [12 L.Ed.2d 977, 84 S.Ct. 1758] and People v. Dorado (1965) 62 Cal.2d 338 [ 42 Cal.Rptr. 169, 398 P.2d 361]; (4) that his confession made in Captain Hocker's office was involuntary; (5) that, even assuming it was voluntary and that he had been properly advised of his rights in accordance with Escobedo and Dorado, defendant, because of his then physical condition was unable to make an intelligent waiver of such rights; (6) that defendant's confession at the prison hospital was involuntary; (7) that the trial court committed prejudicial error in admitting in evidence, over defendant's objections, certain photographs of the victim's body; (8) that the trial court committed prejudicial error by failing to instruct the jury on diminished capacity with respect to malice aforethought; (9) that the prosecutor committed prejudicial misconduct during his closing argument to the jury; (10) that the denial of appointed counsel for defendant in connection with his postconviction remedies constituted a denial of due process and equal protection of law; (11) that the exclusion from the trial jury of persons opposed to the death penalty denied defendant his rights guaranteed by the Sixth and Fourteenth Amendments of the United States Constitution; and (12) that the application of the mandatory death penalty to Penal Code section 4500 constitutes a denial of equal protection of law. As we shall explain, we have concluded that, on the record which has been made complete since our first opinion, defendant's fourth contention above has merit and his conviction should be reversed. In view of this conclusion, we deem it unnecessary to discuss defendant's other contentions.

We have no doubt that, if our inquiry were confined to the testimony of Captain Hocker as to events transpiring in his office, which testimony is corroborated by that of defendant on voir dire, we would be compelled to the conclusion that the confession was properly received. Thus, as we have noted, Captain Hocker advised defendant of his constitutional rights in the manner required by Dorado, and defendant personally testified that the captain made no threats or promises which tended to induce the statements defendant made; that defendant understood these warnings; that he knew he had the right to an attorney and the right to remain silent if he chose to do so; that he knew that anything he might say could be used against him, but that he told Captain Hocker he wanted to talk about what happened in the clothing factory; and that he told the captain the truth of what had happened.

There are, however, other matters which bear on the admissibility of the confession. When the prosecution proposed that Captain Hocker testify as to the content of the conversation in his office, defense counsel objected on the ground of involuntariness based on events taking place immediately before defendant entered the office. On voir dire the captain then testified that at the time defendant entered the office he "appeared to have sustained an injury" about the face, and "was bleeding slightly from the nose." When the captain had seen the defendant a few minutes before the interview while he was being taken from the clothing factory to the prison adjustment center, no injuries were apparent. Defendant testified on voir dire that his first recollection after the events leading up to the killing was of lying on the floor in the adjustment center and being kicked about the head, face, heart and groin by each of four correctional officers; that he sustained a broken nose and received some "cuts" and "bumps" and "had a lot of bruises on my arms and on my back and legs"; that he was made dizzy by the abuse; that his clothing was removed; and that on leaving the cell to go to the captain's office he was again kicked in the back. It also appeared on voir dire that a medical technician was called to attend defendant while he was in Captain Hocker's office but only after the captain had taken defendant's statement. The technician closed a laceration around defendant's eye with six stitches, and treated him for head injuries. Defendant remained dizzy while he was in the captain's office and was removed to the hospital later that day.

Defendant's claim that his confession to Captain Hocker was involuntary, and his further claim that he made no intelligent waiver of his constitutional rights were also supported by People's voir dire Exhibit No. 1. Such document, a proper part of the record on appeal (Cal. Rules of Court, rule 33 (a), (b) and (c)), was not before this court on our first review. It was not received during the trial as evidence bearing on the issue of defendant's guilt, but was received for consideration by the trial court as bearing on the question of the admissibility of the confession made in Captain Hocker's office. It consists of a transcript of the interview with defendant conducted by the deputy district attorney between 3 and 3:30 p.m., which interview took place after the Hocker confession. It is abundantly clear from the transcript itself, the pertinent portions of which are set out below, that defendant was denied the right to counsel during this interview. The prosecution made no attempt to place the contents of the transcript before the jury. Although the document is merely cumulative of certain factual matters bearing on the question of the admissibility of the Hocker confession (e.g., the fact that defendant had been beaten by correctional officers), it also establishes that defendant had confessed or at the very least had made damaging admissions during the beating, which fact had not otherwise been established on voir dire. Thus, defendant stated: ". . . Then they get me over here. They pick me up. They told me I stab a man. I told them that I stabbed him, but that's the last I remember." And again in response to the question, "You told them you stabbed Mr. Canning?" defendant answered, "Yes."

On the foregoing record on voir dire, the trial court concluded that the confession given to Captain Hocker was not coerced. We are not necessarily bound by such determination. We have on numerous occasions made clear our responsibilities in such matters and the nature and scope of our review. [1] These rest upon the fundamental principle that the "use in a criminal prosecution of involuntary confessions constitutes a denial of due process of law under both the federal and state Constitutions." ( People v. Trout (1960) 54 Cal.2d 576, 583 [ 6 Cal.Rptr. 759, 354 P.2d 231, 80 A.L.R.2d 1418]; see People v. Berve (1958) 51 Cal.2d 286, 290 [ 332 P.2d 97]; Payne v. Arkansas (1958) 356 U.S. 560, 561 [2 L.Ed.2d 975, 977, 78 S.Ct. 844].) [2] We said in Berve: "As a reviewing court it is our duty to examine the uncontradicted facts to determine independently whether the trial court's conclusion of voluntariness was properly found. [Citations.][] [3] In exercising this function the court recognizes that the burden is on the prosecution to show that a confession was voluntarily given without previous inducement, intimidation or threat. [Citations.]" (51 Cal.2d at pp. 290-291.) Thus in making an independent examination of the record to ascertain whether defendant's statements were voluntary we follow a practice of the United States Supreme Court which is both well established (see cases in fn. 11, ante) and currently adhered to. (See Greenwald v. Wisconsin (1968) 390 U.S. 519 [20 L.Ed.2d 77, 88 S.Ct. 1152]; Clewis v. Texas (1967) 386 U.S. 707, 708 [18 L.Ed.2d 423, 425, 87 S.Ct. 1338]; Davis v. North Carolina (1966) 384 U.S. 737, 741-742 [16 L.Ed.2d 895, 898-899, 86 S.Ct. 1761].)

[4] "If an individual's `will was overborne' or if his confession was not `the product of a rational intellect and a free will,' his confession is inadmissible because coerced. These standards are applicable whether a confession is the product of physical intimidation or psychological pressure. . . ." ( Townsend v. Sain (1963) 372 U.S. 293, 307 [9 L.Ed.2d 770, 782, 83 S.Ct. 745], quoting from Reck v. Pate (1961) 367 U.S. 433, 440 [6 L.Ed.2d 948, 953, 81 S.Ct. 1541]; and Blackburn v. Alabama (1960) 361 U.S. 199, 208 [4 L.Ed.2d 242, 249, 80 S.Ct. 274].) [5] In determining whether the defendant's confession is the product of a rational intellect and a free will, the totality of the circumstances surrounding the confession must be taken into account. ( Reck v. Pate, supra, 367 U.S. 433, 440 [6 L.Ed.2d 948, 953, 81 S.Ct. 1541]; Payne v. Arkansas (1958) 356 U.S. 560, 567 [2 L.Ed.2d 975, 980, 78 S.Ct. 844]; Fikes v. Alabama (1957) 352 U.S. 191, 197 [1 L.Ed.2d 246, 250, 77 S.Ct. 281]; and see Greenwald v. Wisconsin, supra, 390 U.S. 519.) [6] Factors of significance in assessing the effect of circumstances on the voluntariness of a confession include the mental level and intelligence of the accused ( People v. Lara (1967) 67 Cal.2d 365, 386 [ 62 Cal.Rptr. 586, 432 P.2d 202]; Fikes v. Alabama, supra, 352 U.S. 191, 193 [1 L.Ed.2d 246, 248, 77 S.Ct. 281]; see Payne v. Arkansas, supra, 356 U.S. 560, 567 [2 L.Ed.2d 975, 980, 78 S.Ct. 844]; Mallory v. United States (1957) 354 U.S. 449, 455 [1 L.Ed.2d 1479, 1483, 77 S.Ct. 1356]); the amount of physical abuse or psychological pressure to which the accused was subjected ( People v. Jones (1944) 24 Cal.2d 601, 609 [ 150 P.2d 801]; People v. Siemsen (1908) 153 Cal. 387, 394 [95 P. 863]); the existence of a prior coerced confession ( People v. Brommel (1961) 56 Cal.2d 629, 634 [ 15 Cal.Rptr. 909, 364 P.2d 845]; People v. Jones (1944) 24 Cal.2d 601, 609 [ 150 P.2d 801]; People v. Johnson (1871) 41 Cal. 452, 455; Leyra v. Denno (1954) 347 U.S. 556, 561 [98 L.Ed. 948, 952, 74 S.Ct. 716]; compare United States v. Bayer (1947) 331 U.S. 532, 539-541 [91 L.Ed. 1654, 1659-1660, 67 S.Ct. 1394]; Lyons v. Oklahoma (1944) 322 U.S. 596 [88 L.Ed. 1481, 64 S.Ct. 1208]; see 79 Harv.L.Rev. 935, 1027-1028), and the existence of any break in the chain of events from the initial application of coercion to the time of confession sufficient to insulate the latter from the coercive influences. ( Clewis v. Texas, supra, 386 U.S. 707, 710 [18 L.Ed.2d 423, 426, 87 S.Ct. 1338]; Leyra v. Denno, supra, 347 U.S. 556, 561 [98 L.Ed. 948, 952, 74 S.Ct. 716]; United States v. Bayer, supra, 331 U.S. 532, 540-541 [91 L.Ed. 1654, 1660-1661, 67 S.Ct. 1394]. See Brooks v. Florida (1967) 389 U.S. 413, 414-415 [19 L.Ed.2d 643, 645-646, 88 S.Ct. 541].)

In the case at bench, defendant had received only a fifth or sixth grade education, with a record of failures and poor attendance, and had manifested difficulty with the English language. Expert testimony indicated defendant's mental level and intelligence to be "borderline retarded," "low average or borderline defective," and of a "borderline deficiency caliber." He was beaten in the adjustment center within 30 minutes before his confession to Captain Hocker; he was kicked a final time upon leaving the cell in the adjustment center to go to the captain's office; he was given a towel to place on his bleeding face; he was dizzy and remained dizzy while in the captain's office. As a result of the beating the defendant required several stitches and eventual hospitalization. His interrogator, while not personally involved in the beating, was in charge of the guards responsible for the violence. In addition, Captain Hocker did not attempt to provide medical aid to defendant until after the confession had been elicited. Of especial significance, however, was the fact that defendant had already confessed to the guards who had administered the beating. As we have already pointed out, at no time during the trial did the prosecution make any attempt to answer much less contradict defendant's testimony as to the physical abuse he had received.

[7] The rule has been long and well settled in this state that where a defendant, subjected to threats, violence or other improper influences, makes a confession or other incriminating statement in such a coercive atmosphere and shortly thereafter again incriminates himself under circumstances not manifestly coercive "there is a presumption that the influence of the prior improper treatment continues to operate on the mind of the defendant and that the subsequent confession is the result of the same influence which rendered the prior confession inadmissible, and the burden is upon the prosecution to clearly establish the contrary. [Citations.]" ( People v. Jones, supra, 24 Cal.2d 601, 609; see also People v. Brommel, supra, 56 Cal.2d 629, 634; People v. Loper (1910) 159 Cal. 6, 14-15 [ 112 P. 720, Ann. Cas. 1912B 1193]; People v. Johnson, supra, 41 Cal. 452, 454-455.) Almost a hundred years ago, this court clearly expounded this rule in the Johnson case where an interval of two days occurred between the involuntary statements of the accused and subsequent statements introduced against them at trial: "[It] is equally clear that if their confession or statement, made before the examining magistrate two days thereafter, was a repetition of the statement [involuntarily] made to the Sheriff, or any material portion of such previous statement, the entire statement or confession made to and before the examining magistrate should have been excluded as evidence, by reason of the same having been originally made under such inducements held out to them as to exclude the first confession. The law presumes the subsequent confession to have been made and influenced by the same hopes and fears as the first, and this presumption continues until it is affirmatively established by the prosecution that the influences under which the original confession was made had ceased to operate before the subsequent confession was made. [Citations.]" (Italics added.) ( People v. Johnson, supra, 41 Cal. 452, 454-455.)

In People v. Jones, supra, 24 Cal.2d 601, the defendant after being physically abused made a confession to police officers in Los Angeles which the uncontradicted evidence established was not free and voluntary. As the court observed "Undoubtedly because of the circumstances under which it was made, it was not offered in evidence." (24 Cal.2d at p 608.) However, the prosecution introduced into evidence an incriminating statement by the defendant to San Diego officers three days later under circumstances not manifestly coercive. After giving recognition to the presumption stated above the court in Jones continued: "The determination of the extent of the influence persisting at the time the subsequent confession is made rests, of course, upon attendant circumstances, and the inquiry is whether, considering the age and intelligence of the defendant, the nature and degree of the influence, and the time intervening between the confessions, it can be said that defendant was not induced to confess by reason of the pressure which motivated him to make the first statement, or was not influenced so to do by reason of the prior confession itself." (24 Cal.2d at p. 609.) We thus concluded from the uncontradicted facts that the San Diego confession was not voluntary because "under all of the circumstances the entire situation . . . is so inherently coercive that its very existence is irreconcilable with the possession of the mental freedom essential to a valid confession." (24 Cal.2d at p. 610.)

[8] In the instant case there was no break in the chain of events extending from the physical abuse defendant suffered at the hands of the correctional officers to his immediately following confession made to Captain Hocker. During this time defendant had no opportunity to reassess his situation free from all but the normal disciplinary pressures of prison life. (See United States v. Bayer (1947) 331 U.S. 532, 541 [91 L.Ed. 1654, 1660, 67 S.Ct. 1394].) As he had not been warned that his prior confession made during the beating could not be used against him, the fact that he had made it continued to act as a coercive influence, since "defendant might have concluded that he could not make his case worse than he already had made it. . . ." ( People v. Jones, supra, 24 Cal.2d 601, 610.) There was no effort to provide defendant with medical treatment or to otherwise alleviate the continuing physical and psychological effects of the beating. (See People v. Berve, supra, 51 Cal.2d 286, 292.) In light of the essential contemporaneity of the brutality and the confession to Captain Hocker, the existence of the prior coerced confession, the lack of assurances that further violence would be prevented, and defendant's borderline mentality, the constitutional warnings given by Captain Hocker cannot be viewed as a significant break in the chain of events. (Cf. Sims v. Georgia (1967) 389 U.S. 404 [19 L.Ed.2d 634, 88 S.Ct. 523].) Finally, it is highly significant that here, as in Jones, defendant's previous statements made to the correctional officers were not offered in evidence, undoubtedly because of the circumstances under which they were made. (See People v. Jones, supra, 24 Cal.2d at p. 608.)

We are satisfied from the totality of the circumstances established by the uncontradicted facts in the record that defendant's confession made to Captain Hocker was in fact coerced and not the product of a rational intellect and a free will. We hold that such confession was involuntary and that its use before the jury denied defendant due process of law guaranteed by the Fourteenth Amendment to the Constitution of the United States. Our conclusion that it was involuntary rests not only on our conviction that "defendant's will was overborne at the time he confessed" ( Reck v. Pate, supra, 367 U.S. 433, 440 [6 L.Ed.2d 948, 953, 81 S.Ct. 1541]; Fikes v. Alabama, supra, 352 U.S. 191) and that the use of the confession offends a "sense of justice" ( Brown v. Mississippi (1936) 297 U.S. 278, 286 [80 L.Ed. 682, 687, 56 S.Ct. 461]; Chambers v. Florida (1940) 309 U.S. 227 [84 L.Ed. 716, 60 S.Ct. 472]) but also on society's "`deep-rooted feeling that the police must obey the law while enforcing the law. . . .'" ( Blackburn v. Alabama (1960) 361 U.S. 199, 207 [4 L.Ed.2d 242, 248, 80 S.Ct. 274]; see also People v. Ditson (1962) 57 Cal.2d 415, 436-439 [ 20 Cal.Rptr. 165, 369 P.2d 714].)

Because the confession made to Captain Hocker was involuntary, it was error to receive it in evidence, and the judgment must be reversed for that reason alone, if not for any other. [9] "It is now axiomatic that a defendant in a criminal case is deprived of due process of law if his conviction is founded, in whole or in part, upon an involuntary confession, without regard for the truth or falsity of the confession, Rogers v. Richmond, 365 U.S. 534 [5 L.Ed.2d 760, 81 S.Ct. 735], and even though there is ample evidence aside from the confession to support the conviction. Malinski v. New York, 324 U.S. 401 [89 L.Ed. 1029, 65 S.Ct. 781]; Stroble v. California, 343 U.S. 181 [96 L.Ed. 872, 72 S.Ct. 599]; Payne v. Arkansas, 356 U.S. 560 [2 L.Ed.2d 975, 78 S.Ct. 844]." ( Jackson v. Denno (1964) 378 U.S. 368, 376 [12 L.Ed.2d 908, 915, 84 S.Ct. 1774, 1 A.L.R.3d 1205].)

As to all other claims of error there disposed of and except as qualified by this opinion, we adhere to our opinion in People v. Sanchez, supra, 65 Cal.2d 814. Since we must reverse the judgment we deem it unnecessary to consider other claims of error raised by defendant and not decided here or in our prior opinion. We do not, therefore, determine the admissibility of defendant's second confession to Captain Hocker made in the hospital the day following the crime. In the event of retrial, questions as to the admissibility of that confession, insofar as its constitutional validity comes into issue, will be governed by the standards set forth by the United States Supreme Court in Miranda v. Arizona (1966) 384 U.S. 436 [16 L.Ed.2d 694, 86 S.Ct. 1602, 10 A.L.R.3d 974] ( People v. Doherty (1967) 67 Cal.2d 9, 17 [ 59 Cal.Rptr. 857, 429 P.2d 177]) as well as by the standards set forth in this opinion and in People v. Jones, supra, 24 Cal.2d 601, 609-610.

The judgment is reversed.

Traynor, C.J., Peters, J., Tobriner, J., Mosk, J., and Burke, J., concurred.