dissenting.
Under Brady v. Maryland, 373 U.S. 83, 83 S.Ct. 1194, 10 L.Ed.2d 215 (1963), and United States v. Agurs, 427 U.S. 97, 96 S.Ct. 2392, 49 L.Ed.2d 342 (1976), the defendants were entitled to have the district court examine the INS file of the key government witness because there was a substantial basis for claiming that it might contain material information.
My disagreement with the majority concerns the threshold the defendants must cross before they are entitled to have the court review the information they seek. The majority rejects the Brady claim because the defendants have not yet shown that the file contains material information favorable to the defense or that the information would have created a reasonable doubt that did not otherwise exist. In my view, this is the wrong standard to apply before the defendants have seen the file. We have here a specific request prior to trial, as in Brady, and the Supreme Court explained the prosecutor’s duty in Agurs:
Although there is, of course, no duty to provide defense counsel with unlimited discovery of everything known by the prosecutor, if the subject matter of such a request is material, or indeed if a substantial basis for claiming materiality exists, it is reasonable to require the prosecutor to respond either by furnishing the information or by submitting the problem to the trial judge. When the prosecutor receives a specific and relevant request, the failure to make any response is seldom, if ever, excusable.
427 U.S. at 106, 96 S.Ct. at 2399 (emphasis supplied). Here the prosecutor turned the file over to the judge, but the judge refused to review it.1 In this situation the same standard — “substantial basis for claiming materiality” — should apply, for where the *637trial judge refuses to examine the material, the defendant is in essentially the same position he would have been in if the prosecutor had failed to respond. Surely we cannot expect the defendants to prove the file contains favorable information before they have been permitted to see it.2
In refusing to examine the file, the district judge relied on a government attorney’s representation that there was no agreement which conditioned Gutierrez’ continued residence on his cooperation with the government. I doubt that the court was entitled in these circumstances to rely on the government’s representation.3 Even if reliance on the government’s representations could in some cases be justified, reliance was not appropriate in this case. First, the government represented only that there was no agreement with Gutierrez; it did not represent to the court that the INS file did not contain exculpatory or impeaching information. The district court’s and majority’s emphasis on the presence or absence of an explicit agreement is therefore misplaced. To be useful in impeachment, the file need not show explicit promises; other information that might be in the file could prove useful in cross-examination. Whether a deal actually had been made is less significant than Gutierrez’ belief or disbelief that there had been a deal, United States v. Onori, 535 F.2d 938, 945 (5th Cir.1976), and this witness’ beliefs might be shown by circumstantial evidence in the file.4 Second, the government attorney who represented that no deal existed also said he was not familiar with basic facts in the file. When he was asked about the content of DEA Agent Arreguin’s testimony at the INS hearing (perhaps crucial information), the attorney said he did not know who had testified at the hearing.
Applying the correct standard where the court has refused to review the information, there is a substantial basis for claiming that Gutierrez’ INS file might contain significant impeachment information. Gutierrez’ heroin conviction made him a de-portable alien, and the INS sought to deport him in 1981. DEA Agent Arreguin testified on Gutierrez’ behalf regarding his cooperation with the DEA, and the immigration judge waived deportability. Gutierrez testified at trial that he had thought deportation was “virtually automatic” and that he had fully expected to be deported. Most significantly, he also claimed he did not know what the DEA had done on his behalf or what Arreguin had said at the hearing. Under these circumstances, defendants are entitled to have a neutral court examine the file. I would vacate the convictions and remand to the district court for review of the material; if that review revealed information which would have provided a substantial basis for cross-examination, the defendants should receive a *638new trial. United States v. Deutsch, 475 F.2d 55, 58 (5th Cir.1973); United States v. Austin, 492 F.Supp. 502, 505-06 (N.D.Ill. 1980).5
I therefore respectfully dissent.
. The district court’s impatience upon being asked to review the file after the trial had begun was quite understandable. However, it is far . from clear that the defendants were responsible for the delay. Although the trial transcript is somewhat ambiguous, it appears that the file was subpoenaed sometime before trial, but that the government was unable to locate the file until the lunch break on the first day of trial. Tr. at 67-70.
. The standards at issue in Agurs and applied by the majority here are the standards of "materiality" to be applied to evidence after its contents are known. 427 US. at 107-14, 96 S.Ct. at 2399-402. The "substantial basis for claiming materiality" standard applies to the prosecutor’s duty to respond to specific requests before the defendant and the court have seen the evidence. 427 U.S. at 106, 96 S.Ct. at 2399.
. In the closely analogous situation of a Jencks Act question, this court has insisted that after the defense counsel has raised the issue of access to a witness’ statements,
the court should dispose of it on its own responsibility based upon what it ascertains in a hearing. The court should not make a final disposition upon the representations of government counsel. It cannot escape its duty to learn the truth firsthand.
United States v. Keig, 320 F.2d 634, 637 (7th Cir.1963) (vacating conviction), conviction aff’d after remand, 334 F.2d 823, 825 (7th Cir.1964). See Goldberg v. United States, 425 U.S. 94, 108-09, 96 S.Ct. 1338, 1347, 47 L.Ed.2d 603 (1976) (district court must inspect documents sought under Jencks Act); United States v. O’Brien, 444 F.2d 1082, 1086-87 (7th Cir.1971) (vacating convictions where district court failed to review witnesses' statements under Jencks Act). See also Korman v. United States, 486 F.2d 926, 931 (7th Cir.1973) (requiring sworn affidavit denying use of electronic surveillance).
. ' In this case, because Gutierrez was subjected to extended cross-examination and impeachment, I would not require a new trial if the file would have provided only cumulative impeachment material. See Zeigler v. Callahan, 659 F.2d 254, 266-67 (1st Cir.1981); United States v. Mackey, 571 F.2d 376, 389 (7th Cir.1978).
. I note that the government’s only stated reason for not producing the file was that it contained Gutierrez’ address. In its brief on appeal, the government argues that the defendants already knew Gutierrez' address, so the reason for not disclosing the file now appears to be moot. Unless the government could show another substantial reason for keeping the file confidential, I would not require that the district court’s review of the file be in camera.