PER CURIAM Opinion; Partial Concurrence and Partial Dissent by Judge RYMER.

OPINION

We consider whether the district court erred in denying Kulvir Singh Barapind’s habeas corpus petition challenging the certification of his extradition to India.

*747 FACTS 1

Barapind, a native and citizen of India, is a prominent leader of the All India Sikh Student Federation. The Federation is dedicated to establishing an independent sovereign Sikh nation. From the mid-1980s through the early 1990s, while Bara-pind was still in India and an active Federation member, Sikh insurgents frequently clashed with the Indian government and its supporters, resulting in tens of thousands of casualties.

In 1993, Barapind came to the United States using a passport bearing a false name and was immediately detained by the Immigration and Naturalization Service (INS). He applied for asylum and withholding of deportation, asserting that he would face persecution if he were returned to India, but the immigration judge denied relief and ordered him excluded. On ha-beas review, a panel of this court affirmed the district court’s remand to the Board of Immigration Appeals, finding that the immigration judge committed legal errors. See Barapind v. Rogers, 114 F.3d 1193 (9th Cir.1997) (mem.). Barapind’s asylum proceedings were then interrupted by India’s request that the United States extradite him. 2

India requested Barapind’s extradition pursuant to its extradition treaty with the United States. 3 See Quinn v. Robinson, 783 F.2d 776, 782 (9th Cir.1986) (“The right of a foreign sovereign to demand and obtain extradition of an accused criminal is created by treaty.”). The Treaty provides for extradition of a person suspected of committing certain crimes when the evidence of the person’s guilt would be sufficient to bring him to trial in the United States if his crimes had been committed here. See art. 9. Certification of extradition is lawful only when the requesting nation has demonstrated probable cause to believe the accused person is guilty of committing the charged crimes. See Quinn, 783 F.2d at 783 ; see also Cornejo-Barreto v. Seifert, 218 F.3d 1004, 1009 (9th Cir.2000).

The United States filed a complaint on India’s behalf and requested a warrant to bring Barapind before an extradition court for a hearing to determine extraditability. See 18 U.S.C. § 3184 . The district court issued the warrant, Barapind-was transferred from INS custody and the district court conducted an extradition hearing. 4

India sought Barapind’s extradition based on crimes arising out of eleven separate incidents. The extradition court denied certification of extraditability for the crimes relating to eight of the incidents, concluding either that India failed to show probable cause to suspect Barapind of the crimes, or that extradition was inappropriate because the crimes were covered by the Treaty’s political offense exception, *748 which bars extradition for crimes “of a political character.” See art. 6. The court certified extradition for offenses stemming from the three remaining incidents.

Barapind petitioned for a writ of habeas corpus, arguing that the charges for which his extradition was certified were not supported by probable cause or fell under the political offense exception. 5 The district court denied his petition, and Barapind appealed. A three-judge panel of this court affirmed, see 360 F.3d 1061 (9th Cir.2004), and we subsequently voted to rehear the case en banc, see 381 F.3d 867 (9th Cir.2004) (order).

ANALYSIS

Because our review of the district court’s decision on questions of law and mixed questions of law and fact is de novo, see Quinn, 783 F.2d at 791-92 , and because the district court on habeas review accepted the factual findings of the extradition court, we focus on the extradition court’s opinion. , Thus, we. determine whether the extradition court erred in certifying extraditability for crimes arising out of three incidents, designated as FIR 100, FIR 89 and FIR 34. 6

General Challenges to Extraditability

Barapind asserts two claims applicable to all three incidents.

1. First, he contends that India’s evidence against him was incompetent. Barapind focuses on the fact that the witness statements, produced by India were unsigned translations, on which the extradition court should not have relied.

Barapind misunderstands the nature of extradition proceedings. “With regard to the admissibility of evidence, the general United States extradition law requires only that the evidence submitted be properly authenticated.” Emami v. United States Dist. Court, 834 F.2d 1444, 1451 (9th Cir.1987). The authentication requirements for documentary evidence are contained in 1. 8 U.S.C. § 3190 , which specifies that “the certificate of the principal diplomatic or consular officer of the United States resident in such foreign country shall be proof that [submitted documents] are authenticated in the manner required.” Here, it is undisputed that the evidence presented against Barapind was properly authenticated pursuant to section 3190, and the Treaty itself contains no supplementary authentication requirements. We therefore reject Barapind’s claim that the extradition court erred in relying upon -the authenticated documentary evidence submitted by India. Barapind also argues that the evidence against him is unreliable because it was fabricated or obtained by torture. The extradition court, however, conducted a careful, incident-by-incident analysis 'as to whether- there was impropriety on the part of the Indian government. Its findings that the evidence regarding FIR-100, FIR 89 and FIR 34 was not the product of fabrication or torture were not clearly erroneous. See Mainero v. Gregg, 164 F.3d 1199, 1205 (9th Cir.1999) (“Factual determinations by a ... judge in an extradition proceeding are reviewed for clear error.”).

2. Next, Barapind claims that because some of the charges for which India *749 requested his extradition were deemed to be political offenses, he cannot be extradited on any charges, even those not covered by the political offense exception. He bases his argument on article 6 of the Treaty, which protects a fugitive from extradition if “he proves that the requisition for his surrender has, in fact, been made with a view to try or punish him for a crime or offence of a political character.”

Barapind reads this language as preventing a fugitive’s extradition if any of his charged offenses were crimes of a political character. But he can point to no authority for such a drastic interpretation. Nor is his argument consistent with the doctrine of specialty, which “prohibits the requesting nation from prosecuting the extradited individual for any offense other than that for which the surrendering state agreed to extradite,” Quinn, 783 F.2d at 783 , and which is incorporated into the terms of the Treaty, see art. 7 (“A person surrendered can in no case be ... brought to trial ... for any other crime or offence ... than those for which the extradition shall have taken place....”). The "doctrine of specialty suggests the more general proposition that an extradition court should consider each offense separately in determining whether an extradition requisition is based on a political crime. The fact that some crimes are found to be non-extraditable political offenses has no bearing on whether certification of extradition is appropriate for crimes that are not political offenses.

Incident-Specific Challenges

Finding both of Barapind’s universal challenges to the extradition court’s decision to be meritless, we turn to his incident-specific claims.

1. FIR 100. India charges Barapind with murder and attempted murder, alleging that he drove a scooter while a gunman riding with him killed one man and wounded another. Barapind contends that India did not establish probable cause to believe he committed these crimes.

In reviewing an extradition court’s probable cause determination for evidentiary sufficiency, we ask whether the court’s finding was supported by “competent evidence.” See Mainero, 164 F.3d at 1205 (quoting Zanazanian v. United States, 729 F.2d 624, 626 (9th Cir.1984)). To establish probable cause, India relied in significant part upon a translated statement of Makhan Ram, the man who was wounded in the shooting, identifying Barapind as the driver. Barapind attempted to destroy probable cause by submitting a more recent affidavit from Makhan ^herein he claims that he never identified Barapind. This affidavit states that the Indian police forced Makhan to sign a blank sheet of paper, which they subsequently turned into affidavits identifying Barapind.

The extradition court recognized that a fugitive facing extradition can present his own evidence to explain away the requesting government’s evidence of probable cause. See Singh, 170 F.Supp.2d at 994; see also Mainero, 164 F.3d at 1207 n. 7 (“Generally, evidence that explains away or completely obliterates probable cause is the only evidence admissible at an extradition hearing, whereas evidence that merely controverts the existence of probable cause, or raises a defense, is not admissible.”). The court concluded, however, that “the credibility of Makhan Ram’s recantation cannot be determined without a trial,” Singh, 170 F.Supp.2d at 1024, which would exceed the limited mandate of an extradition court in making a determination of probable cause, as opposed to ultimate guilt.

The extradition court was supported by competent evidence in finding *750 that Barapind did not obliterate India’s showing of probable cause, as Makhan’s more recent affidavit constituted conflicting evidence, the credibility of which could not be assessed without a trial. Because extradition courts “do[ ] not weigh conflicting evidence” in making their probable cause determinations, Quinn, 783 F.2d at 815 , we find no basis for overturning the extradition court’s decision that probable cause of Barapind’s guilt existed with respect to FIR 100.

2. FIR 89. The extradition court also certified extraditability for an incident involving four murders allegedly committed by Barapind' and three accomplices after they invaded a house. Barapind’s group went to the home of Sohan Singh and his wife looking for Sohan’s three sons, who were thought to be police collaborators. Barapind immediately shot and killed two of the sons, and the group asked Sohan’s wife where the third son was. She told the assailants that he was sleeping in another room. Barapind’s accomplices went to the room and killed the third son along with his wife, Kulwant Kaur.

Before the extradition court, Barapind argued that he could not be extradited based on the crimes 'arising out of this incident, as they were non-extraditable political offenses under article 6 of the Treaty. The court agreed that the murders of the three sons were political offenses, but it certified extradition for the murder of Kulwant. Barapind challenges this certification.

To determine whether the political offense doctrine bars extradition, we apply a two-prong “incidence test.” For a crime to qualify as “one of a political character,” Treaty art. 6, there must be: “(1) the' occurrence of an uprising or other violent political disturbance at the time of the charged offense, and (2) a charged offense. that is ‘incidental to’ ‘in the course of,’ or ‘in furtherance of the uprising,” Quinn, 783 F.2d at 797 (footnotes and citations omitted).

There is no real doubt that the crimes Barapind is accused of committing occurred during a time of violent political disturbance in India. As the extradition court noted, ,“[t]ens of thousands of deaths and casualties” resulted between the mid-1980s and early 1990s as Sikh nationalists clashed with government officers and sympathizers in Punjab. Singh, 170 F.Supp.2d at 1032. Substantial violence was taking place, and the persons engaged in the violence were pursuing specific political objectives. Cf. Quinn, 783 F.2d at 807 .

The dispute between the parties concerns the “incidental to” prong, which asks whether. Barapihd’s crimes were “causally or ideologically related” to the political uprising. Id. at 809 . In Quinn , we discussed the “incidental to” analysis in depth, stating that extradition courts should focus not on the types of acts alleged, but rather on the motivation for those acts. See id. at 809-10 .

The extradition court found that it was-not bound by Quinn’s discussion of the “incidental to” prong. This part of our opinion was “dicta,” the court stated, because Quinn’s extraditability was ultimately based on his failure to satisfy the “uprising” prong.. The court explained that our discussion of “incidental to” was not necessary to our ultimate disposition of Quinn , and our ruling on the issue was therefore not binding. See Singh, 170 F.Supp.2d at 998.

The extradition court operated under a mistaken understanding of what constitutes circuit law. In Quinn , the proper scope of “incidental to” was an issue presented for review. We addressed the is *751 sue and decided it in an opinion joined in relevant part by a majority of the panel. Consequently, our articulation of “incidental to” became law of the circuit, 7 regardless of whether it was in some technical sense “necessary” to our disposition of the case. 8 See Cetacean Cmty. v. Bush, 386 F.3d 1169, 1173 (9th Cir.2004); Miranda B. v. Kitzhaber, 328 F.3d 1181, 1186 (9th Cir.2003) (per curiam); United States v. Johnson, 256 F.3d 895, 914-16 (9th Cir.2001) (en banc) (Kozinski, J., concurring). The extradition court thus erred in concluding that it was not required to follow Quinn . 9

The court nonetheless reached the correct result, as Barapind failed to demonstrate that Kulwant’s murder was a political offense. Indeed, even though it mislabeled the Quinn articulation of “incidental to” as dicta, the court properly concluded that Barapind’s proffered evidence would not satisfy the Quinn formulation. See Singh, 170 F.Supp.2d at 1036-37. Under Quinn , a court may not rely on a fugitive’s mere assurance that a crime had some political purpose. Rather, the fugitive has the burden of showing a factual nexus between the crime and the political goal. In this case, all we know about Kulwant is: (1) she was the wife of a suspected police collaborator; and (2) Bar-apind’s crew did not intend to kill her based on any of her political beliefs or *752 affiliations. But we do not know why Bar-apind’s accomplices did, in fact, kill Kul-want. Was it an accident? Was it because she attempted to interfere with the murder of her husband? Or were the men attempting to eliminate witnesses ■ who could later identify them — and, if so, why didn’t they also kill Sohan and his wife?

Barapind has not answered any of these questions. As the extradition court noted, he has provided no evidence at all to explain the motive for Kulwant’s murder. See Singh, 170 F.Supp.2d at 1036. Without such evidence, there is no basis for finding that the murder was a political offense under Quinn . Because Barapind. failed to prove that his charge fell under the political offense exception, the extradition court properly certified his extradita-bility for Kulwant’s murder.

Barapind also argues that there was insufficient evidence to establish probable cause of his guilt. He was not in the room when Kulwant was killed, and. he contends that India did not show he shared his accomplices’ intent to kill her. The extradition court, however, found that Barapind came to the house with his accomplices, personally shot and killed two men and waited while the accomplices went to kill the third man and Kulwant. While these facts alone might not be sufficient to prove beyond a reasonable doubt that Barapind shared his accomplices’ intent to murder Kulwant, they do provide competent evidence for finding probable cause of Barapind’s guilt as an accomplice or co-conspirator. 10 See Quinn, 783 F.2d at 815 ; see also Collins v. Loisel, 259 U.S. 309, 316 , 42 S.Ct. 469 , 66 L.Ed. 956 (1922) (“The function of the committing magistrate is to determine whether there is competent evidence to justify holding the accused to await trial, and not to determine whether the evidence is sufficient to justify a'convietion.”).

3. FIR 34. Finally, the extradition court certified extradition based on India’s allegation that Barapind was one of the men responsible for committing four murders that occurred during a shootout between Sikh insurgents and an Indian government officer, a former officer and their bodyguards. The strongest evidence India produced to support its charges was the affidavit of a police inspector who claimed that an eyewitness, Nirmal Singh, identified Barapind as one of the shooters. Barapind responded with an affidavit from Nirmal stating that he never identified Barapind or any other participant in the shootout. The extradition court determined that Barapind’s evidence was insufficient to destroy probable cause, concluding that a trial would be required to determine who was telling the truth. See Singh, 170 F.Supp.2d at 1028. The court was justified in making this decision. See Quinn, 783 F.2d at 815 ; see also pages 756-57 infra.

Barapind also claims that the crimes included in FIR 34 constituted political offenses. The extradition court recognized that all of the victims were agents or former agents of the Indian government, and that India charged violations of its Terrorist and Disruptive Activities Act (TADA). Nevertheless, the court found that Barapind did not establish that the charged crimes were political offenses, as “[w]hether this attack was a domestic terrorist attack or politically motivated ean- *753 not be determined.” Singh, 170 F.Supp.2d at 1035.

As noted above, however, the extradition court incorrectly concluded that it was not bound by Quinn’s interpretation of the political offense exception. Further, unlike its discussion of FIR 89, see Singh, 170 F.Supp.2d at 1036-37, the extradition court’s discussion of FIR 34 did not explain how the court would apply Quinn’s “incidental to” analysis to Barapind’s case. This is particularly important given that there is at least some evidence, including the affiliation of the victims with the Indian government and India’s charging of TADA violations, that might suggest the crimes were political offenses. We remand for consideration of how the Quinn political offense analysis applies to the crimes charged in FIR 34.

CONCLUSION

We affirm the district court’s denial of Barapind’s habeas petition with respect to FIR 100 and FIR 89. We reverse as to FIR 34. Given that extradition is proper on two of the grounds specified by the extradition court, we remand to the district court to determine whether it is necessary and appropriate to revise its ruling as to FIR 34. ■

AFFIRMED IN PART; REVERSED IN PART; AND REMANDED.

. For a complete description of the facts, see the extradition court's thorough opinion in In re Extradition of Singh, 170 F.Supp.2d 982 (E.D.Cal.2001). We set forth only those facts relevant to this appeal.

. Barapind unsuccessfully challenged the interruption of asylum proceedings. See Barapind v. Reno, 225 F.3d 1100, 1114 (9th Cir.2000).

. The relevant treaty is, as the parties have stipulated, the Treaty for the Mutual Extradition of Criminals Between the United States of America and Great Britain, Dec. 22, 1931, U.S.—Gr. Brit., 47 Stat. 2122 , made applicable to India in 1942, see Treaty Affairs Staff, United States Dep’t of State, Treaties in Force 132 (1999).

.The hearing was held before District Judge Oliver W. Wanger. See 18 U.S.C. § 3184 . Judge Wanger was also the district judge who considered and denied Barapind's petition for a writ of habeas corpus, the decision currently on appeal before us. See note 5 infra.

. Decisions of an extradition court are not directly reviewable but may be challenged collaterally by a petition for habeas corpus. See Mainero v. Gregg, 164 F.3d 1199, 1201-02 (9th Cir.1999).

. “FIR” stands for First Information Report, a summary report prepared by the Indian police when certain serious crimes are committed. The litigants have used the FIR designations to refer to the incidents from which ■Barapind's charges' arise. We follow this convention.

. Any statement to the contrary in McMullen v. INS, 788 F.2d 591, 598 (9th Cir.1986), is overruled.

. The partial dissent claims that our "discussion about dicta is dicta.” Dissent at 758. However, we need not go back very far to find an en banc court — the body charged with "maintainpng ] uniformity of the court's decisions,” Fed. R.App. P. 35(a)—announcing a binding legal principle for three-judge panels and district courts to follow even though the principle was technically unnecessary to the court's disposition of the case before it. In Miller v. Gammie, 335 F.3d 889 (9th Cir.2003) (en banc), we held that “where the reasoning or theory of our prior circuit authority is clearly irreconcilable with the reasoning or theory of intervening higher authority,” id. at 893 , three-judge panels and district courts "should consider themselves bound by the intervening higher authority and reject the prior opinion of this court as having been effectively overruled,” id. at 900 . Of course, this holding was not strictly necessary to our disposition of the case, for we.were sitting en banc and thus were not required to follow prior circuit law in any event. Nevertheless, we announced the rule to guide three-judge panels and district courts in deciding which precedents were binding on them.

Likewise, in Atonio v. Wards Cove Packing Co., 810 F.2d 1477 (9th Cir.1987) (en banc), we held that a three-judge panel faced with contradictory controlling precedents “must call for en banc review.” See id. at 1478-79 . Again, this holding, which we subsequently reaffirmed en banc, see United States v. Hardesty, 977 F.2d 1347, 1348 (9th Cir.1992) (en banc) (per curiam), would have been nonbinding "dicta” by the dissent’s definition. See dissent at 759.

Our opinion provides a supervisory function similar to Miller and Atonio by instructing three-judge panels and district courts about how to determine what law is binding on them. It thus constitutes authoritative circuit law. See Miller, 335 F.3d at 904 (Tashima, J., concurring) ("[W]hen the en banc court exercises its supervisory authority over three-judge panels, its decisions should be recognized as authoritative and binding,” even with respect to matters that are “not necessary to the decision of the case.”).

. Because the offenses at issue in this case present relatively straightforward applications of the political offense exception, we have no occasion to consider whether to endorse in all cases Quinn’s statement that, in deciding whether an. act is incidental to a political uprising, "[a]ll that the courts should do is determine whether the conduct is related to or connected with the insurgent activity.” 783 F.2d at 810 . We leave for another day the question whether some exceptional circumstances might arise in which the relationship between the political goal and the act would be too tenuous to fall under the political offense exception.

. The extradition court certified Barapind's extradition based on his charge of murder under Sections 302 and 34 of the Indian Penal Code. Section 34 provides that a person is guilty of a "criminal act ... done by several persons in furtherance of the common intention of all.”