joined by FLETCHER, PREGERSON, REINHARDT, and TASHIMA, Circuit Judges, dissenting:
In a deft move that would make Joseph Heller proud,1 the majority tells us that a juvenile suspect, arrested near the scene of a violent murder by a Navajo Tribal Officer and held in custody for questioning by federal agents, merits the protection of neither the laws of the Navajo Nation nor the United States, both of which require parental notification prior to questioning. Tribal law matters not, the majority tells us, because the juvenile was prosecuted in federal, not tribal, court and no violation of federal law occurred because he was in tribal, not federal custody. To avoid this conundrum, the juvenile must engage in the sisyphean task of proving that he was put in this situation as a result of a conspiracy specifically designed and carried out to avoid the requirements of federal law. The result is all the more problematic as it is the government’s burden to prove that a statement has been made as the result of a knowing, intelligent, and voluntary waiver of one’s rights — a burden the district court has already found the government failed to meet on the facts of this case.
■ District judges in this circuit hear thousands of cases each year in which they must make factual determinations. In doing so, they weigh evidence and assess the credibility of witnesses. These factual determinations are required in a wide variety of matters — from judging whether probable cause exists for an arrest or search or, as in this *1080ease, whether the government met its burden to prove the knowing, intelligent, and voluntary nature of a Miranda waiver. In making the factual judgments that underlie the admissibility of such a statement, district courts are, as they should be, accorded substantial discretion. It is, after all, the district court that sees the witnesses, listens to, and compares the witness accounts. Consistent with the breadth of that discretion, we rarely demand that the district court make detailed fact findings — especially when no party has asked that it be done. We simply look to the record to see if the evidence shows that the district court’s determination was not clearly erroneous. See, e.g., United States v. Bernard S., 795 F.2d 749, 751 (9th Cir.1986).
Here, the district court did exactly what was required of it. The government sought to use the statement of a seventeen-year-old Navajo with a ninth-grade educational level who had been heavily drinking as well as abusing drugs and other substances over a twelve-hour period. The interview, done in other than his native tongue, took place at 5:00 o’clock in the morning and, despite the requirements of both tribal and federal law, before his parents were notified of his arrest. See Navajo Code tit. 9, § 1107 A; 18 U.S.C. § 5033. After hearing both sides on the issues and listening to the somewhat conflicting testimony of the arresting Navajo Tribal Officer and the FBI Special Agent who conducted the interview, the district court concluded “on the whole record that [Doe’s] waiver was [not a] knowing and intelligent and voluntary relinquishment of a known right.”
A more routine handling of a criminal proceeding in a district whose docket is heavily influenced by major crimes in Indian Country would be hard to find. Yet the majority insists that the district court do it all over again. This time, the majority insists, the defendant must not only prove his statement was involuntary, he must prove the existence of a “conspiracy” between tribal and federal authorities to deprive him of his rights.
There is no question but that Doe’s parents were not notified and were not present during his interview. This is not the sole basis for the district court’s determination that the government had not met its burden of establishing the admissibility of Doe’s statement. Instead, after hearing testimony from Tribal Officer Tsosie and Agent Burke of the FBI, the district court concluded, “on the whole record,” that Doe’s waiver was not voluntary, knowing, and intelligent.
The majority pays lip service to our standards of review but then proceeds to sit as a fact-finder. Doe’s waiver was voluntary, the majority concludes, because, after a twelve-hour drug and drinking' binge and no sleep for an entire night, Doe appeared coherent and lucid to Tsosie and Burke at 5:00 o’clock in the morning. Yet the district court also heard evidence that Doe had consumed the intoxicant, “ocean,” just before his arrest, that he appeared under the influence of alcohol as recently as 2:00 a.m., that his eyes were bloodshot, and that he appeared tired. Moreover, due to the conflicting testimonies of Tsosie and Burke, see infra, the district court could properly question the credibility of the officers, especially doubting their emphatic testimony regarding Doe’s condition.
The majority next recites our deferential clear error standard of review for determining whether a waiver is knowing and intelligent and then finds the district court’s conclusion “implausible.” The majority concedes, as it must, that parental absence is a factor the district court may consider in determining the admissibility of a statement taken from a juvenile in these circumstances, see United States v. Indian Boy X, 565 F.2d 585, 591-92 (9th Cir.1977), but then dismisses it as a non-factor. To the majority, parental notification is relevant only if the juvenile’s demeanor indicates he needs his parents’ advice or if he asks that his parents be notified. Maj. op. at 1075-76. In enacting 18 U.S.C. § 5033, however, Congress disagreed. Section 5033 reflects a policy decision by Congress that parents of juveniles in federal custody must be immediately notified of the arrest and the juvenile’s rights. It is not the juvenile’s decision to make. This is because a juvenile may need the advice of his parents or guardians who better understand the stakes involved, whether or not the juvenile thinks he needs it. Given the totality of the circumstances — Doe’s ninth-grade educational level, lack of. criminal history, physical condition, native language of Navajo, and lack *1081of a parent or attorney being present — the district court’s finding that Doe’s waiver was not knowing and intelligent seems entirely plausible.
So why are we sending this matter back to the district court? Good question. The answer certainly cannot be to gain a more complete record on the condition of Doe or the physical circumstances of his interrogation. The majority apparently wishes more detail in the record about the relationship between tribal and federal authorities.
Doe was in federal custody during his interrogation, .and § 5033 should apply. This was an investigation of a murder, as the FBI made clear in the first moments of Doe’s interview. Because the murder took place on the Navajo Reservation, only federal authorities had jurisdiction over the crime; neither the tribe nor any state official had the slightest jurisdiction over the crime for which Doe was held for questioning by federal authorities. See 18 U.S.C. §§ 1151, 1153. That is why Officer Tsosie took Doe into custody, notified the FBI, and then held him until FBI Agent Burke arrived. That is why Agent Burke conducted the interview and Officer Tsosie simply observed. We could easily take judicial notice of this jurisdictional framework. See Fed.R.Evid. 201. Because it is such a routine and commonplace event in a district like Arizona, the district court undoubtedly did the same by simply taking it as a given.
The suggestion that Doe was under “tribal arrest on tribal charges” is suspect at best. Tribal police discovered two violent crime scenes, with two dead bodies and three other seriously injured victims. They found Doe near the second crime scene, covered with blood. Yet the majority suggests that tribal police arrested Doe with the intent of charging him with a tribal misdemeanor. Officer Tsosie never questioned Doe regarding an assault, and no tribal charges were ever filed against Doe in tribal court. Instead, from the beginning, this was a murder investigation — subject to exclusive federal jurisdiction. Moreover, all the possible crimes that Doe could have been charged with — manslaughter, kidnapping, assault with intent to commit murder, assault with a dangerous weapon, assault resulting in serious bodily injury, burglary, robbery — are governed exclusively by federal law. See 18 U.S.C. § 1153(a).
Officer Tsosie acknowledged the close cooperation between tribal and federal authorities when investigating a murder in Indian country. His testimony on this point is definitive: he testified that he held Doe in a squad car at the murder scene and “waited for Agent Burke to arrive.” He agreed that it was “routine” for an FBI agent to take over an “investigation for federal prosecution and not for the purposes of a tribal investigation.”2 During the interrogation of Doe, Agent Burke asked all the questions. Officer Tsosie simply signed the waiver form as a witness.
The district court was also faced with -glaring inconsistencies between the testimonies of Tsosie and Burke, for example, whether Burke knew Doe was a juvenile before the interrogation began. Officer Tsosie emphatically testified that Agent Burke asked Doe if he was a juvenile and if he wanted his parents present for the interrogation.3 Agent *1082Burke testified that he did not ask Doe’s age until after the interrogation or if Doe wanted his parents present. Moreover, Agent Burke stated that, even if he had known that Doe was a juvenile, he would have interrogated Doe without first notifying Doe’s parents.4
The end result is that the government avoids the requirements and restrictions of both tribal and federal law. If Doe had been tried in tribal court, the statement would be inadmissible. See Navajo Trib.Code tit. 9, § 1107 A. But a violation of tribal law would probably not preclude the admission of a defendant’s statement in federal court. See, e.g., United States v. Chavez-Vernaza, 844 F.2d 1368, 1372 (9th Cir.1987) (evidence obtained in violation of state law but in compliance with federal law is admissible in federal court). The government escapes compliance with federal law, however, because the majority asserts that Doe was in tribal custody.
The majority holds that Doe will be considered in “federal custody” only if he can prove that tribal and federal police conspired to deny Doe’s federal procedural rights. See Maj. op. at 1078. This “conspiracy” standard exalts form far above substance and sets the bar much too high for juvenile criminal defendants. A juvenile should be considered in “federal custody” if tribal custody is done to further the interests of a federal investigation. Here, tribal police arrested Doe and held him for federal authorities so he could be interrogated about crimes solely within federal jurisdiction. This working arrangement between tribal and federal police is entirely routine and should not work to deprive tribal juvenile arrestees of their federal statutory rights.5
*1083We would affirm the district court’s well-documented and routine determination concerning Doe’s statement to federal authorities. If our standards of review are to mean anything, they must be consistently applied in every situation, whether the government or the criminal defendant prevails in a suppression hearing.
. “If you are crazy, they have to take you out of combat, but the catch is you have to ask them, and if you're trying to get out of combat then you can’t be crazy.” Jacob Brackman, Catch 22 Casebook 363 (Frederick Kiley & Walter McDonald, eds., 1973) (reviewing Joseph Heller, Catch 22 (1961)).
. Q. (Defense counsel): At the time that you arrived at the scene, from the beginning to the end, were you considered the lead investigator on the case?
A. (Tsosie): Up to when Agent Burke arrived.
Q. So when Agent Burke arrived, he actually took over the investigation, is that what your testimony is?
A. Yes.
. Q. (Defense counsel): Is there a [Navajo] Department of Public Safety policy for interrogating or interviewing juveniles?
A. (Tsosie): Yes.
Q. And what is that policy?
A. If the person wants their parents there, we usually try to get their parents there during the interview.
Q. And you were present during the interviews; is that correct?
A. Yes.
Q. Did anyone ask [Doe] if he wanted his parents present?
A. Yes.
Q. And who was that?
A. Agent Burke.
Q. And are you positive of that?
A. That he asked that question?
Q. Yes.
A. Yes.
Q. Do you recall what portion of the interview Agent Burke informed or advised [Doe] that he could have his parents present?
A. During the beginning.
*1082Q. However, you can recall specifically that he was given the opportunity to have his parent present. Is that your testimony?
A. Yes.
Q. And how was it that you are so sure that Agent Burke had advised him that he could have his parents present?
A. How I am so sure?
Q. Yes.
A. Cause I remember him asking.
Q. Were there any preliminary questions asked, for instance, his age, his education, his background?
A. Yes.
Q.... Did you — were you aware that he was only 17 at the time?
A. [Doe]?
Q. Yes.
A. Yes.
. Q. (Prosecutor) Now, did you discuss with him whether or not he wished to have a parent present?
A. (Burke) I don't recall that.
Q. And any particular reason that you’re not' — that you’re aware of that you did not ask him about his parent?
A. No.
Q. (Defense counsel) At the time you observed [Doe], were you able to determine or did you even attempt to determine whether or not he was a teenager, an adult, or his age— any age, I should say?
A. I don’t think I even attempted.
Q. Did it ever cross your mind, prior to asking him his age, that he may be a juvenile?
A. I don’t think it ever came up.
Q. Well, I guess my question is, based on your experience and what you observed, did it ever cross your mind that the person that you were interrogating was a juvenile?
A. I don’t think it ever did cross my mind.
Q. Nowhere in your report does it say that [Doe] requested that his parents be present; is that correct?
A. That’s correct.
Q. And so you did not ask him if he wanted his parents to be present; is that correct? A. I don’t recall asking him that.
Q. And, in fact, at least in your mind, you would have had no reason because you didn’t know he was a juvenile; is that correct?
A. I wouldn’t have — that’s a fair statement.
Q. Is there an FBI policy for interrogating juveniles?
A. For interviewing juveniles that are in federal custody, yes there is.
Q. And in your — and what is that policy?
A. Without referring to the manual, I believe, in a nutshell it says, they're not to be interviewed pending, perhaps, consultation with the U.S. Attorney's office. I'm not exactly sure how it reads, but in a nutshell, they're not to be interviewed.
Q. And you are free to interview any juvenile who may be a suspect as long as he’s not in federal custody?
A. As long as he’s not in federal custody, yes, sir.
. United States v. Alvarez-Sanchez, 511 U.S. 350, 114 S.Ct. 1599, 128 L.Ed.2d 319 (1994), and United States v. Juvenile Male, 74 F.3d 526 (4th Cir.1996), do not support the majority's new "conspiracy” standard. Alvarez-Sanchez simply stands for the proposition than 18 U.S.C. § 3501 applies only to persons in federal custody. See *1083511 U.S. at 358, 114 S.Ct. 1599. The question before this court is not whether § 5033 applies only to detainees in federal custody, but what constitutes federal custody. Juvenile Male mere-Iy holds that administrative detention pending deportation proceedings is not “custody for an alleged act of juvenile delinquency.” See 74 F.3d at 530.