The child, age 13, appeals an order of the juvenile court that he is within its jurisdiction because of conduct that, if done by an adult, would constitute intentional murder. He assigns as error that the court denied his motion to suppress a confession that he made after the police gave him Miranda warnings. He argues that he did not make a knowing, intelligent and voluntary waiver of his rights before he confessed. He also assigns as error that, at the suppression hearing, the court admitted testimony by police about previous encounters with the child. We review de novo. ORS 419.561(4); State ex rel Juv. Dept. v. Gray, 79 Or App 216, 218, 718 P2d 773 (1986); State ex rel Juv. Dept. v. Qutub, 75 Or App 298, 300, 706 P2d 962, rev den 300 Or 332 (1985). We affirm.
On June 3,1987, after the victim’s body was found in the Sycan Ford area, police arrested the child and took him to the Klamath County Sheriff’s office. An officer explained to the child that he wanted to question him about “the event” at Sycan Ford. Without giving Miranda warnings, the officer began to interrogate him. About fifteen minutes later, a second officer arrived. The first officer testified that the child appeared frightened and appeared to believe that one of the officers would hit him when he arrived at the sheriffs office. The officer testified that, shortly after the second officer arrived, they drove the child to a park about one mile from the sheriffs office to calm him and walked to a spot hidden from the road. The officers kept other people away while they questioned the child for another 45 minutes, again without giving him Miranda warnings. They testified that the child seemed to calm down at the park. During that questioning, the child confessed for the first time to the killing. He then became upset and asked to return to the sheriffs office. The officers drove him back to the office.
At the sheriffs office, the officers asked the child if he would make a taped statement, and he agreed. While the two officers taped the interrogation, the child sat between them. The officers testified that the child became relaxed and put his feet up on the desk during the interrogation, that they made no threats toward or promises to him and did not deny him food or drink and that he did not appear to be under the influence of drugs or alcohol. The interrogation lasted about *43940 minutes. Without receiving Miranda warnings, the child confessed for the second time.
The police then asked the child to make diagrams of the death site, and he did so. The record does not disclose how much time the child took to make the drawings. While he drew the diagrams or shortly thereafter, the officers realized that neither of them had given him Miranda warnings. Within an hour after the conclusion of the first taped interrogation, the officers started a second taped interrogation. They first read Miranda warnings to the child:
“[OFFICER]: OK, before I start I’ll go ahead and advise you of your rights, and we’re going to go through the incident that occurred down at the Sycan Ford, OK?
“[THE CHILD]: All right.
“[OFFICER]: OK, my duty as a police officer is to inform you of your rights. You have the right to remain silent, anything you say can and will be used against you in a court of law. You have the right to talk to a lawyer and have him present with you while you are being questioned, if, or you’re being questioned. If you cannot afford to hire a lawyer, one will be appointed to represent you before being questioned if you wish. If you do give a statement, you can stop talking anytime you wish. Do you understand these rights?
“[THE CHILD]: Yeah.
“[OFFICER]: Having these rights in mind, do you want to discuss the incident that —
“[THE CHILD]: Huh?
“[OFFICER]: Having these rights in mind, do you want to go ahead and talk to me?
“[THE CHILD]: Uh, yeah.”
After the officers recommenced questioning the child, one of them stopped to have him sign the advice of rights card. The card contained the same warnings that the officer had just read to him. It also contained the question, “Do you understand these rights?” The child answered, “Yes.” The card also contained the question, “Having these rights in mind, do you wish to talk to us?” The child answered, “Yes, ah, ya.” The child and the officer then both signed the card. During the subsequent interrogation of about a half an hour, the child confessed the third time.
*440The child moved to suppress the evidence of any statements that he had made to the police, asserting that the state obtained them in violation of his Fifth and Sixth Amendment rights. The controversy centers on the third confession. At the suppression hearing, over the child’s objection, the court admitted testimony of several police officers who had a connection with this case to show, as the state argued below, that the child “has had multiple encounters with the police and * * * previously had his Miranda rights explained to him and he has previously made choices necessary with regard to whether he was going to exercise his Miranda rights or not.” During some, but not all, of the encounters, the police had given him Miranda warnings. During one encounter, when he did receive warnings, he asked for an attorney, and the officer ceased to question him.
The court denied the motion to suppress. It reasoned that it must look at the totality of the circumstances, including whether the unwarned confessions were voluntarily given, to determine whether the child knowingly, intelligently and voluntarily waived his rights when he gave his third confession. It ruled that the child’s first two confessions, although unwarned, were voluntary. It also found that, before the third confession, the police gave Miranda warnings and asked him if he understood them and that he replied that he did. It found that the child had exercised his Miranda rights in the past and had then understood the warnings. It found:
“So, I make a finding that the Miranda warning was made, that he had sufficient understanding of the warning, he knew the topic or nature of the investigation, he knew what the officer was asking him about, he was a youngster with sufficient background and experience to make a decision on his own behalf. I find that there were no inducements, no promises, no threats, no expectations of leniency.”
It concluded:
“So I find that, considering the total circumstances, that the waiver was knowing, was intelligent and it was voluntary and with respect to the tape number 2 [the third confession], the Motion to Suppress is denied.”
The child assigns as error that, at the suppression hearing, the court admitted the police officers’ testimony about his previous encounters with the police. He asserts that *441the ruling violates OEC 404(3). That rule, however, does not apply to
“[t]he determination of questions of fact preliminary to admissibility of evidence when the issue is to be determined by the court under [OEC 104].” OEC 101(4)(a).
The evidence that the state presented of the child’s earlier encounters with the police when he did receive Miranda warnings was relevant to the issue of the child’s knowing, intelligent and voluntary waiver of his Miranda rights before the third confession, and the court could admit it. Evidence of previous interrogations during which the child did not receive Miranda warnings was irrelevant. On de novo review, we disregard that evidence.
On the merits of the denial of the suppression motion, the child argues, as he did below, that, under the Fifth Amendment, considering the totality of the circumstances, he did not knowingly, intelligently and voluntarily waive his Miranda rights. Miranda v. Arizona, 384 US 436, 444, 86 S Ct 1602, 16 L Ed 2d 694 (1966); see also Johnson v. Zerbst, 304 US 458, 58 S Ct 1019, 82 L Ed 1461 (1938). Although he based his motion to suppress on the Fifth and Sixth Amendments, he does not raise the Sixth Amendment on appeal. He also does not argue that, under the Fifth Amendment, the failure of the police to give him Miranda warnings before the first two confessions made his third confession inadmissible as a matter of law or that the first two confessions or his drawings were involuntarily made. The issue is whether, under the Fifth Amendment, the state proved that, when he gave his third confession, he waived his Miranda rights knowingly, intelligently and voluntarily.
Under the Fifth Amendment, as the child recognizes, the failure of the police to give him Miranda warnings before his first two voluntary confessions does not render the third confession inadmissible purely as a matter of law. In Oregon v. Elstad, 470 US 298, 314, 105 S Ct 1285, 84 L Ed 2d 222 (1985), the Supreme Court held that
“absent deliberately coercive or improper tactics in obtaining the initial statement, the mere fact that a suspect has made an unwarned confession does not warrant a presumption of compulsion.”
*442On the other hand, that the police warned the child before the third confession does not mean that his waiver of rights was knowing, intelligent and voluntary as a matter of law. Rather, we must examine the totality of the circumstances, including the entire course of police conduct. See Oregon v. Elstad, supra, 470 US at 318; Schneckloth v. Bustamonte, 412 US 218, 226, 93 S Ct 2041, 36 L Ed 2d 854 (1973); United States v. Wauneka, 770 F2d 1434, 1440 (1985).
Elstad permits v. to consider, as part of the totality of the circumstances, that the child had made earlier voluntary confessions and drawings, that he knew of their existence and that he made them without Miranda warnings. As the court stated in Elstad:
“A subsequent administration of Miranda warnings to a suspect who has given a voluntary but unwarned statement ordinarily should suffice to remove the conditions that precluded admission of the earlier statement. In such circumstances the finder of fact may reasonably conclude that the suspect made a rational and intelligent choice whether to waive or invoke his rights.” 470 US at 314. (Emphasis supplied.)
If a properly warned confession follows an unwarned but clearly voluntary confession,
“a careful and thorough administration of Miranda warnings serves to cure the condition that rendered the unwarned statement inadmissible. The warning conveys the relevant information and thereafter the suspect’s choice whether to exercise his privilege to remain silent should ordinarily be viewed as an ‘act of free will.’ ” 470 US at 310. (Emphasis supplied.)
This case, however, may not be an “ordinary” one. The child was 13 years old. The interrogations before the challenged waiver, although they were made during the daytime, had taken place while the child was held in custody for almost four hours. During that entire period, he was isolated from persons other than the police. He was first interrogated in the sheriffs office, then in the park and then back in the sheriffs office. The police testified that he appeared to relax before the first confession but that, after he made it, he again became upset and asked to return to the sheriffs office. He again appeared to relax before the second confession. The testimony does indicate that, at certain times in the interviews, the child was frightened and tense. Although the record *443states that he is able to read, is an “eager student” and a “bright youngster,” it also shows that he has had no formal education except for recent short periods of tutoring that a school district had provided.
On the other hand, the officers made no threats or promises to the child, did not deprive him of food, drink or sleep and did not deceive him. They clearly explained to him the nature of the investigation. It also appears that he replied after hearing the Miranda warnings that he understood them and wished to answer the officers’ questions nonetheless, and he also signed the advice of rights card. The record contains no reference to the child being upset, tense or frightened when he orally waived his Miranda rights or when he signed the rights card. The trial judge had the opportunity to hear the child’s testimony and to observe his demeanor in court. He stated that he found that the child had “sufficient understanding of the warning, he knew the topic or nature of the investigation, he knew what the officer was asking him about.” We agree with those conclusions.
Finally, the child does not assert that he involuntarily made the drawings after the second confession. His oral and written waivers of Miranda rights were made less than one hour after he made the drawings. If those drawings were voluntarily made, the record does not disclose any intervening facts that would justify a conclusion that his waiver of Miranda rights was involuntary.
Under the totality of the circumstances, we conclude that the state has carried its burden to prove that the child knowingly, intelligently and voluntarily waived his rights. The court did not err when it denied the motion to suppress the third confession.
Affirmed.