BERNSTEIN, Chief Justice.

This is an appeal by Richard Shaw from a conviction of the crime of grand theft. The evidence adduced at the trial showed the following facts: During the evening of September 11, 1961, two officers of the Pima County Sheriff's office were driving in an unmarked car to investigate an occurrence unrelated to this case. As they passed the fenced equipment yard of the Burris-White Machinery Company they observed an automobile parked at the side of the road with a micro-midget racer protruding from the trunk compartment. One of the occupants of the automobile was motioning for traffic on the road to drive past the parked or slowly moving automobile. The officers made a U-turn to investigate and as they drew abreast of the automobile they flashed their spotlight on its occupants. The automobile drove off at high speed and a chase ensued.

During the chase, the racer fell from the trunk of the automobile. Shortly thereafter the officers discovered the automobile abandoned in an empty lot. The officers traced the registration to Joseph Brown, and subsequently took him into custody. He admitted his part in taking the racer from the Burris-White yard and implicated Ronald Alkire and the defendant.

Brown pleaded guilty to a charge of accessory after the fact to the crime of grand theft, and received a suspended sentence. Alkire and the defendant were tried for the crime of grand theft. Alkire was acquitted and a mistrial granted as to the defendant. At a second trial defendant was found guilty and now appeals.

Defendant assigns as error the trial court's refusal to admit into evidence in its entirety defendant's Exhibit A. Exhibit A consisted of a confession signed by Joseph Brown who appeared as a state's witness at Shaw's trial. The portions excluded consisted of statements by the witness that he had committed crimes other than the one for which he was arrested. The defendant argues that Brown's admission of other crimes makes him dependent upon the leniency of the law enforcement officials for whom he was testifying in this case, and that the fact of such admissions may be shown to establish bias. In State v. Holden, 88 Ariz. 43, 352 P.2d 705 (1960) and State v. Little, 87 Ariz. 295, 350 P.2d 756 (1960) we held that a party could establish, by means of cross-examination, the existence of facts of a like nature which tended to show bias. Here, however, the defendant sought to establish these facts by the introduction of extrinsic evidence, rather than by cross-examination of the witness whose bias he desired to show. This raises the question whether a foundation for the introduction of evidence showing bias of a witness must be laid by first cross-examining the witness himself. This court, in Ross v. State, 23 Ariz. 302, 203 P. 552 (1922) adopted, without extended discussion, the majority rule that such a foundation is required. We have taken this opportunity to re-examine the ruling in that case, and now reaffirm it. A minority of the courts (see Annot. 16 A.L.R. 984 (1922)) hold that it is not necessary to establish a foundation for extrinsic evidence of bias by cross-examination. Some draw distinction between statements showing bias and acts showing bias, and require a foundation only in the former case. We think this distinction too tenuous to be material. One purpose of the foundational cross-examination is to give the witness a fair opportunity to explain statements which, standing alone, tend to show bias, People v. Sweeney, 55 Cal.2d 27, 9 Cal.Rptr. 793, 357 P.2d 1049 (1961). We think a witness should have the same opportunity to explain equivocal acts which, if unexplained, tend to show bias. A second reason for the rule is to promote expediency in the conduct of trials. If facts showing bias are admitted by the witness, it is unnecessary to introduce the extrinsic evidence, McCormick, Evidence § 40 (1954); Ross v. State, supra. We think this is the principal justification for the rule, and if the court is satisfied that fairness will be maintained, it has discretion to dispense with the requirement of the foundational cross-examination where exceptional circumstances would make it unduly burdensome to require it (as, e.g. where the witness has been excused before the opposing party learns of facts showing bias, cf. State v. Carns, 136 Mont. 126, 345 P.2d 735 (Mont. 1959)). We hold in this case it was not error to refuse to admit Brown's confession where there was no preliminary cross-examination of Brown in regard to the facts offered to show bias.

The defendant contends that he was improperly limited in his cross-examination of Brown as to the matters in the excluded portion of Exhibit A. He further contends that he was improperly limited in his cross-examination of another witness concerning the appearance of the defendant at the time he made oral confession, during a hearing before the court on the voluntariness of that confession. We are unable to find in the record any place where testimony on these matters was elicited by questions of defendant's counsel and excluded by the court. These assignments are without merit.

The defendant was limited by the court in his attempt to cross-examine the investigating officer in regard to the matter the officer was enroute to investigate at the time the automobile containing the racer was observed. He argues that he should have been permitted to continue this line of cross-examination to determine if the officer had prior information that the three youths were going to enter the Burris-White equipment yard. He cites State v. Holden, 88 Ariz. 43, 352 P.2d 705 (1960) where we said:

"A defendant in a criminal prosecution has an absolute right to cross-examine an adverse witness, and if at all within the proper bounds, such right may not be unduly restrained or interfered with by the trial court." 88 Ariz. at 56, 352 P.2d at 715.

In response to questions which were permitted the witness testified that the case which he was investigating had no relationship to the charge against Shaw, and that he had no prior knowledge of an impending attempt to take the racer from the Burris-White yard. The defendant made no offer of proof to indicate what he expected the questioning to disclose. An absolute right to cross-examine "within the proper bounds" does not license the defendant for a fishing expedition into completely irrelevant matter.

The defendant next contends that the trial court erred in considering the defendant's conduct as a juvenile in pronouncing sentence in violation of A.R.S. § 8-228 which states:

"B. The disposition of a child or of evidence given in the juvenile court shall not be admissible as evidence against the child in any proceeding in another court, * * *."

Defendant in his brief states that at the time of pronouncing sentence the trial court received a report from the Adult Probation Officer of Pima County which contained a complete record of the defendant's activities as a juvenile offender. He further states that a transcript of the court's comments on sentencing will clearly reflect that the court considered and relied upon this report in setting the sentence. However, no such transcript was made a part of the record on appeal. We therefore consider the question of this use of juvenile records not appropriate to answer on the state of the record. Statements in the briefs do not substitute for evidence in the record. Hunter v. State, 43 Ariz. 269, 30 P.2d 499 (1934); cf. State v. Thomas, 81 Ariz. 124, 302 P.2d 261 (1956).

The defendant assigns as error the failure of the trial court to exclude evidence of the oral confession made by the defendant to the investigating officers after he was picked up by them. He contends that the confession was obtained during a period when the officers were violating A.R.S. § 8-221:

"A peace officer, other than the probation officer, who arrests a child under the age of eighteen years shall forthwith notify the probation officer, and shall make such disposition of the child as the probation officer directs."

The circumstances surrounding the taking of the confession were these: The defendant was picked up by two police officers at his home about 12:30 or 1:00 a.m. These officers had Alkire and Brown in their custody at the time. Defendant dressed and agreed to go with the officers to the sheriff's office. During the ride to the sheriff's office the defendant complained of being nauseated and the car was stopped so that he could throw up outside of the car. Defendant then indicated that it would be some time before he had to throw up and the group proceeded to the sheriff's office. The officers commenced questioning Alkire and Brown and defendant was left to sit in an outer office. The defendant asked the officers twice to take him to the hospital and complained that he had the "shakes" and was sick. One of the officers obtained two aspirin and gave them to the defendant. Defendant testified that he told the officers again that he had to throw up, that he was directed to a rest room where this was accomplished. Defendant took the stand and stated:

"Well, at first they tried to get me to admit to it. I told them I wouldn't. And so they just let me sit out in the office. I kept getting sick, feeling worse, and I told Bernal that I didn't feel good and would he please take me to the hospital. And he says, `I can't take you to the hospital or anywhere until I get some kind of a statement out of you.' But he said he would go up and get me some aspirin.

* * * * * *

"Q Did they tell you what they were charging you with?

"A No they didn't.

"Q Did anyone, either Officer Dunn, Bernal or Officer Russel ever advise you what you were being charged with?

"A No they didn't.

"Q Did any one of these officers ever say to you you are being placed under arrest and being charged with a crime?

"A No.

"Q Did Officer Bernal ever offer you leniency if you would admit to participating in any alleged crimes that evening?

"A Well, I finally got so sick I felt like I was going to pass out. So I told Bernal that I'd admit to it if he'd either take me to Mother Higgins [juvenile home] or the hospital. And he said all right."

Each of the officers stated he had not threatened the defendant nor promised him leniency if he would make a statement. The defendant was taken to the Mother Higgins Home about 3:30 to 4:00 o'clock a.m. During the two and a half to three hours the defendant was in the custody of the sheriff's officers no attempt was made to call a probation officer because they "didn't think it was necessary."

The philosophy which inspired creation of the juvenile court, and statutes implementing it, is that the state recognizes that in the majority of cases involving antisocial behavior (including criminal offenses) on the part of the youthful offenders, there is both a responsibility and an opportunity for the state, through special treatment in a non-criminal proceeding, to redirect and rehabilitate these young people. This operates for the benefit of the individual, and for society as a whole. However, in many states, as in Arizona, it is also recognized that there are certain individuals still within the chronological classification as juveniles, for whom this special treatment is futile. The juvenile court therefore may refuse to continue its jurisdiction in such cases, and may remand these individuals for regular proceedings in the criminal court. Under the law in Arizona, until the juvenile court, which has exclusive jurisdiction of all delinquent children or children accused of crime, has considered the matter and decided that the particular individual is not one who will benefit from its special treatment, a child offender remains in the juvenile jurisdiction.

While under the juvenile court jurisdiction, a child is under certain disabilities not attaching to an adult. He is not entitled to be released on bail; he does not have the right of trial by jury, or right of compulsory process to compel the attendance of witnesses on his behalf guaranteed by the Arizona Constitution in criminal prosecutions. To compensate for some of these disabilities, the juvenile statutes provide that the juvenile probation officer shall act as a representative in his behalf, and further that if he is arrested by a peace officer, such officer "shall forthwith notify the probation officer, and shall make such disposition of the juvenile as the probation officer directs."

The need for special treatment begins at the instant the juvenile is contacted by peace officers and this was recognized by the legislature. A few hours of the treatment sometimes accorded mature and hardened criminals can give the impressionable mind of a youth an indelibly warped view of society and its interest in him.

That the youthful offender stands before the police interrogators in a different position from that occupied by the mature criminal is recognized. In Oklahoma, confessions of juveniles obtained in the absence of parents or guardian or counsel are inadmissible in evidence, because such defendants are deemed incapable of waiving constitutional and statutory safeguards, unless it appears beyond a reasonable doubt that the minor offenders fully understand the effects of such a waiver, Olivera v. State, 354 P.2d 792 (Okla.Cr. (1960)).

Quite recently the United States Supreme Court held that the admission into evidence of a confession of a juvenile obtained during a five day period when he had seen no friendly adult violated due process standards, although the boy had been informed of his right to counsel, and although the confession was corroborated by earlier statements, Gallegos v. State of Colorado, 370 U.S. 49, 82 S.Ct. 1209, 8 L.Ed.2d 325 (1962). A recognized text on the subject of juvenile delinquency states:

"Because of the child's presumed immaturity, special safeguards should be thrown around a police officer's interview with a child in investigating a delinquent act. In certain situations, depending on the age of the child and the act committed, waiver to criminal court may be a possibility. Moreover at the time of the interview, it is not known whether or not the court specializing in children's cases will retain jurisdiction over the case if a petition is filed, or will waive its jurisdiction and permit the child to be tried in a criminal court. Therefore, it cannot always be assumed that the police interview will lead only to a noncriminal proceeding.

Before being interviewed, the child and his parents should be informed of his right to have legal counsel present and to refuse to answer questions if he should so decide. In cases where waiver is possible, he should also be cautioned that if he answers, his answers may be used not only before the specialized court but possibly in a criminal court. Where a child has been questioned alone by a police officer, without having been given an opportunity to secure the presence of his parents, guardian, or counsel, his statements during such interview should be presumed to have been induced either by the child's immaturity or by the idea that they would be used only in the specialized court and they should, therefore, unless the presumption is overcome, be excluded from admission before a criminal court in which the child may be a defendant." Glueck, The Problem of Delinquency p. 539 (1959) (quoting from a publication of the U.S. Government Children's Bureau.)

Unquestionably, the purpose of A.R.S. § 8-221 was to alter the usual method of handling persons arrested on suspicion or for investigation of criminal activities when those persons are juveniles. Moreover, it is apparent that this alteration of methods was intended to protect the interests of juveniles rather than to facilitate police investigations. Since a major feature of the usual treatment of newly arrested persons is interrogation, it follows that one of the purposes of A.R.S. § 8-221 is to protect the juvenile from the adverse effects of this procedure.

We have carefully considered the possible means of enforcing the policy expressed in A.R.S. § 8-221 and have concluded that the means most in harmony with the purposes expressed and implicit in that section is to preclude the admission of statements obtained by the persuasion of police during the period when the section is being violated. We find support for this ruling in the cases cited above and others in which statements of juveniles are excluded in recognition of the factors of immaturity and fear in the mind of the juvenile which may have induced such statements, e.g. Felder v. State, 17 Ala. App. 458, 85 So. 868 (1920) (based upon an Alabama statute reflecting this policy).

Because of the importance of this ruling, we feel it necessary to explain in some detail the position we now take. A.R.S. § 8-221 requires that following the arrest of a juvenile by an officer other than the probation officer, such officer shall "forthwith" notify the probation officer and follow his instructions for the disposition of the child. "Forthwith" means "immediately, without delay, promptly", Harbel Oil Co. v. Steele, 80 Ariz. 368, 298 P.2d 789 (1956). While the statute does not permit any period of wilful delay, however short, it is complied with if the arresting officer notifies the probation officer at his earliest reasonable opportunity. Moreover, we recognize that a probation officer may not always be immediately available in the less populated counties of the state. A period of detention which otherwise complies with the statutes and during which reasonable efforts are being made to contact the probation officer does not violate A.R.S. § 8-221.

Voluntary statements made during transportation from the scene of arrest or during a period of detention when A.R.S. § 8-221 is not being violated are admissible in accordance with the usual rules of evidence. A conscious effort by the police to take advantage of unavoidable delays in contacting the probation officer, by subjecting the juvenile to interrogation, is contrary to the policy and spirit of A.R.S. § 8-221 and statements obtained by such a procedure are inadmissible.

We consider distinguishable cases in other jurisdictions which have held that a short period of detention and interrogation prior to taking the juvenile to a detention home (where the governing statutes required he be taken immediately) was not illegal. The policy of the controlling statutes in those cases was directed toward the segregation of juveniles from adult offenders. A statutory expression of a policy to protect juveniles from the adverse effects of police interrogation was not a feature of these cases. See, e.g. State v. Smith, 32 N.J. 501, 161 A.2d 520 (1960); Harper v. Strange, 81 U.S.App.D.C. 349, 158 F.2d 408 (D.C. Cir. 1946).

Nor is the salutary procedure of investigating the details of a youth's conduct before charging him with an offense, as expressed in these cases, at issue here. Our rule does not prevent the police from questioning a juvenile — it only prevents them from subjecting the juvenile to formal interrogation without permission of the person appointed by law to see that the interrogation procedure is conducted in a manner consonant with the purposes and policies of juvenile rehabilitation. The legislature has made the decision of public policy in providing for a representative in the person of the probation officer. Certainly in the proper discharge of his duties, the latter would not be acting in the interest of the juvenile or of society merely by preventing interrogation — he could and should only prevent overzealous pressure.

In the present case the defendant's statement was obtained during a period when no effort was made to comply with A.R.S. § 8-221 because the officers "didn't think it was necessary." Under the rule expressed herein the admission of this confession was error.

The judgment is reversed and the case remanded for a new trial.

STRUCKMEYER, JENNINGS and LOCKWOOD, JJ., concur.