concurring.
I agree with the majority that the district court’s order is appealable under Perlman v. United States, 247 U.S. 7, 38 S.Ct. 417, 62 L.Ed. 950 (1918), and subsequent cases interpreting that opinion. I also agree that the CBS materials cannot at this time be obtained by a rule 17(c) subpoena, except to the extent that they may be used for impeachment purposes after the witnesses testify at trial, because they do not meet the evidentiary requirement of rule 17(c).
*197I write separately because I do not believe that our conclusion that the materials may not be produced under rule 17(c) for other than impeachment purposes ends our inquiry. The district court held that even if the materials were not producible under rule 17(c), it had an independent obligation similar to that imposed on the prosecution in Brady v. Maryland, 373 U.S. 83, 83 S.Ct. 1194, 10 L.Ed.2d 215 (1963), to disclose to the defendants any material that it deemed to be “exculpatory.” In light of this holding, I believe that the question whether the district court has an obligation independent of rule 17(c) to release the CBS materials must be reached. Further, I do not believe that the question whether the defendants have demonstrated pursuant to Riley v. City of Chester, 612 F.2d 708 (3d Cir. 1979), that the only practical means of access to the information is through the media should be reached unless it is first determined that the district court had the authority to release the materials.
The CBS materials came into the possession of the district court as a result of our opinion in United States v. Cuthbertson, 630 F.2d 139 (3d Cir. 1980), cert. denied, 449 U.S. 1126, 101 S.Ct. 945, 67 L.Ed.2d 113 (1981) (Cuthbertson I). In Cuthbertson I, we reviewed the district court’s order that CBS produce for in camera inspection before trial: (1) statements of the persons on the government witness list, and (2) statements of all franchisees or potential franchisees. Following the lead of the Supreme Court in United States v. Nixon, 418 U.S. 683, 703, 94 S.Ct. 3090, 3105, 41 L.Ed.2d 1039 (1974), we determined that the question of CBS’s privilege need not be reached unless the requirements of rule 17(c) had been met. In determining whether the requirements of rule 17(c) had been met, we emphasized that the material sought by the rule 17(c) subpoena must be evidentiary and relevant. Cuthbertson I, 630 F.2d at 144. See United States v. Nixon, 418 U.S. at 699-700, 94 S.Ct. at 3103, 3104.
The only evidentiary use that the defendants could advance at that time was that the witness statements could be used for impeachment purposes. We recognized that statements cannot become admissible for impeachment purposes until after a witness testifies inconsistently with such statements. Therefore, ordinarily they are not producible under rule 17(c) until after the witness testifies at trial. However, we held that the district court had not abused its discretion in requiring pretrial production of the witness statements for in camera inspection because such inspection would assist the district court in its preparation for ruling on whether to disclose statements to the defendants at trial. We believed that allowing in camera review would help avoid unnecessary delays and disruptions of the trial. We emphasized that “[u]nder the district court’s order, the defendants will get such statements, if at all, only after the witness testifies at trial.” 630 F.2d at 145.1 It is clear from a review of our opinion in Cuthbertson I that we contemplated that the district court would review the materials in camera only to facilitate its determination whether any statements could be admitted into evidence for impeachment purposes after the witness testified at trial. Further, we admonished that “[cjourts must be careful that rule 17(c) is not turned into a broad discovery device, thereby undercutting the strict limitation of discovery in criminal cases found in Fed.R.Crim.P. 16.” 630 F.2d at 146. See also Gilmore v. United States, 256 F.2d 565 (5th Cir. 1958).
It is equally clear from a review of the district court opinion that the court decided to disclose the statements to the defendants without determining that they were producible under rule 17(c). In fact, the district court implied that the statements could not be reached by a subpoena under rule 17(c) *198because they probably would not be deemed “evidentiary.” The district court, however, did not view the issue to be whether the materials were producible under rule 17(c). Instead, the court stated that it “has an obligation beyond that of disinterested third parties to the administration of justice.” Because it believed that the CBS materials would be helpful to the defense, it found that it had a duty to disclose this information.
Apparently, the district court believed that its duty to disclose these materials arose from the due process clause. The court believed that it had a constitutional duty similar, if not identical, to the duty imposed on the prosecution in Brady to disclose exculpatory evidence to the defendant. Whether the due process clause imposes a Brady -type obligation on federal judges is a substantial question that has not been directly addressed by this court. Cf. United States v. Dansker, 537 F.2d 40, 61 (3d Cir. 1976), cert. denied, 429 U.S. 1038, 97 S.Ct. 732, 50 L.Ed.2d 748 (1977) (Jencks Act obligations apply only to prosecution and not to court). Most of the United States Courts of Appeals that have addressed this issue have held that the requirements of Brady apply only to the prosecution and not to the court itself. See, e. g., United States v. Hutcher, 622 F.2d 1083 (2d Cir. 1980), cert. denied, 449 U.S. 875, 101 S.Ct. 218, 66 L.Ed.2d 96 (1980); United States v. Greathouse, 484 F.2d 805 (7th Cir. 1973). But see United States v. Figurski, 545 F.2d 389 (4th Cir. 1976).
The reluctance of these courts to impose such an obligation on federal judges is understandable. A judge often observes material that may be helpful to a defendant. Such material may come to the judge’s attention in proceedings other than the defendant’s criminal trial or, as in this case, it may come from a source that claims a privilege not to disclose the material to the defendant. The privilege claimed may be absolute, such as the attorney-client privilege, or it may be qualified, as is the first amendment privilege claimed in this case.
When a privilege claim arises, a district court may utilize the in camera device. In camera inspection is often used when a party believes it has materials that should not be disclosed pursuant to a subpoena. See, e. g., United States v. Nixon, 418 U.S. 683, 94 S.Ct. 3090, 41 L.Ed.2d 1039 (1974) (executive privilege); United States v. O’Neill, 619 F.2d 222 (3d Cir. 1980) (executive privilege); In re Grand Jury February 14, 1978 (Markowitz), 603 F.2d 469 (3d Cir. 1979) (attorney-client and fifth amendment privileges). By employing this protective device, the person opposing disclosure can obtain an impartial determination of whether the documents contain material that is producible under the subpoena and, in the case of a qualified privilege, whether such material is subject to disclosure under an appropriate balancing test. In camera inspection provides for this determination without causing the documents to lose their confidential status. In order to protect expectations of confidentiality, we have recognized a judicially created privilege that attaches to information disclosed in the course of an in camera proceeding. See, e. g., Markowitz, 603 F.2d at 474-75. This privilege was created to ensure that such information does not lose its confidential status merely because it has been disclosed to a district judge.
When viewing materials in camera, the district court has important obligations. In United States v. Nixon, the Supreme Court discussed these obligations. Regardless of the strength or weakness or even the applicability of the asserted privilege, the Court recognized that “[i]t is elementary that in camera inspection of evidence is always a procedure calling for scrupulous protection against any release or publication of material not found by the court, at that stage, probably admissible in evidence and relevant to the issues of the trial for which it is sought.” United States v. Nixon, 418 U.S. at 714-15, 94 S.Ct. at 3110-3111.
Given the kinds of material that a district court may view in camera, and the deeply held privacy interest or privilege of the person opposing disclosure, I believe that a district court should consider in camera material to be in its possession for a limited purpose only. Therefore, ordinarily a dis*199trict court should not consider the merits of the asserted privilege, much less decide to disclose the material, until after it has determined that the party seeking disclosure would have the right to compel production of the material if it were still in the hands of the person opposing disclosure. Otherwise, a device intended to protect the person opposing disclosure could be converted into a device by which that person must disclose material that could not have been obtained from it directly. This would not only undermine the integrity of the in camera device but also would greatly expand the discovery rights of criminal defendants. Ironically, this expansion would come at the expense of those third parties who claim to have a privilege not to comply with a criminal defendant’s established discovery rights.2
As the foregoing discussion illustrates, federal judges have important obligations that are not imposed on the prosecution. Therefore, if the due process clause does impose on federal judges a Brady -type obligation to disclose certain materials to a criminal defendant, I believe that such a duty certainly can be no greater than the prosecution’s constitutional duty to disclose exculpatory material when there has been a general, as opposed to a specific, request to produce such material. See United States v. Agurs, 427 U.S. 97, 106-07, 96 S.Ct. 2392, 2398-2399, 49 L.Ed.2d 342 (1976).3 Assuming for purposes of this appeal that such a duty exists, the question remains whether the witness statements in the CBS tapes triggered this duty to disclose.
The prosecution is required to disclose material only when nondisclosure would deprive the defendant of the right to a fair trial. See United States v. Agurs, 427 U.S. 97, 96 S.Ct. 2392, 49 L.Ed.2d 342. In finding that the prosecution’s failure to disclose evidence did not deprive the defendant of her right to a fair trial, the Agurs Court emphasized that the undisclosed evidence must be “constitutionally material.” To determine whether the prosecution’s nondisclosure meets this standard, a court may not use the customary harmless-error standard. According to the Agurs Court, “the constitutional standard of materiality must impose a higher burden on the defendant.” Id. at 112, 96 S.Ct. at 2401. It is not sufficient that the undisclosed evidence might have affected the jury’s verdict. There has been constitutional error only “if the omitted evidence creates a reasonable doubt that did not otherwise exist.” Id. (emphasis added). I believe that the statements in the CBS tapes must be judged under this standard to determine whether the district court had the authority to release them to the defendants.
In this case, the question whether there was a Brady-type obligation to disclose arises in a most unusual posture. In the ordinary Brady case, it is only after a judgment of conviction that a court reviews the failure of the prosecution to disclose material the defendant argues should have been admitted into evidence. In this case, the Brady question has arisen before trial. The Agurs Court, however, reasoned that the same standard logically applies to both an initial decision to disclose and a postconviction determination whether nondisclosure deprived a defendant of his or her due process rights at trial. See id. at 108, 96 *200S.Ct. at 2399. I recognize that because one cannot predict how a trial may develop it is often difficult and somewhat impractical to determine before trial whether the failure to disclose certain material would meet the Agurs standard.4 However, in this particular case the difficulty of predicting the course of the trial is not as crucial as it might otherwise be: if the statements in question are to be produced under a Brady theory, it is because they ultimately will not be admissible at trial. Otherwise, in accordance with our opinion in Cuthbertson I, the district court could order them disclosed under rule 17(c) after engaging in the appropriate balancing. See Cuthbertson I, 630 F.2d at 148.
I have considerable difficulty imagining when the failure to disclose nonevidentiary material could result in a reversal of conviction under the standard announced in Agurs. The Agurs Court made it clear that there is no constitutional obligation on the prosecution to disclose all materials that would be helpful to the defendant in preparing the defense. If there were such an obligation, the prosecution would be obliged to “open its files” because it obviously would be helpful for the defendant to know the government’s entire case, including incriminating, as well as exculpatory, evidence. However, I will assume for purposes of this appeal that there might be a case in which the failure to disclose nonevi-dentiary material could result in a reversal of conviction. I believe that at a minimum such nonevidentiary material would have to lead directly to evidence that meets the standard articulated in Agurs in order to trigger a constitutional duty to disclose. Otherwise, the Brady obligation would be transformed from a minimal constitutional obligation into a constitutional right to discovery.
I have examined the tapes in question and I believe that they do not contain any material that meets the Agurs standard. Because appellate courts have an obligation, similar to that imposed on the district courts, to keep material that we view in camera confidential, I must be circumspect in explaining the nature of the material in the CBS tapes that could be viewed as helpful to the defense. I emphasize that in this review I am concerned only with those statements that ultimately prove to be inadmissible. If the statements prove to be admissible, the district court can order disclosure to the defendants after completing the appropriate balancing.
My review of the CBS tapes convinces me that the district court’s use of “exculpatory” was intended in a very broad sense of that word. I do not disagree with the district court’s conclusion that listening to the tapes or reading the transcripts might assist the defendants in preparing their defense. In these interviews, Mike Wallace plays the role of an adept cross-examiner. He asks leading questions, at times trying to imply that the interviewees might have been somewhat at fault in the failure of the franchising operation. He also questions whether persons of the interviewees’ backgrounds could actually be “duped” into investing into such a scheme. There is no doubt that listening to these questions and to the responses and conversations of the potential government witnesses would benefit the defendants. It would enable them to view the manner in which these potential witnesses handled the equivalent of a rigorous cross-examination and perhaps indicate in which areas of cross-examination the witnesses appear the most likely to falter. However, at no point in these interviews did the interviewees affirmatively indicate that they believed either that the defendants were not at fault or that they themselves were at fault. Their statements would not be admissible for purposes other than impeachment. They do not qualify as statements against interest, nor do they *201appear to meet any other exception to the hearsay rule. Further, I do not believe that the statements would lead the defendants to admissible evidence that would meet the “constitutionally material” standard of Agars. Therefore, even if the district court was correct in deciding that it has a Brady-type obligation, I do not believe that it was a permissible exercise of discretion to find that these materials triggered such an obligation.
For these reasons, I agree that the order of the district court should be reversed.5 Because I do not believe that the district court had the authority to release these statements in the first place, I express no opinion on the conclusion of the majority that the defendants did not meet the burden of demonstrating under Riley v. City of Chester, 612 F.2d 708 (3d Cir. 1979), that they could not obtain this material from a nonmedia source.
. As to the statements of the nonwitness franchisees or potential franchisees, we held that CBS could not be required to produce them even for in camera inspection because the defendants had not made a sufficient preliminary showing that these statements were evidentia-ry. 630 F.2d at 145-46. We found that the defendants’ assertion that these statements might contain some exculpatory material did not justify enforcement of the subpoena under rule 17(c).
. The courts have consistently held that rule 17(c) itself should not be used to expand a criminal defendant’s discovery rights. See, e. g., United States v. Berrios, 501 F.2d 1207 (2d Cir. 1974). A fortiori, I do not believe that in camera inspection to determine whether materials are privileged from disclosure under a rule 17(c) subpoena should be used to expand a defendant’s discovery rights.
. The Brady obligation imposed on the prosecution is based, at least in part, on the adversarial relationship between the prosecution and the defense; it is inherently unfair for the prosecution, which controls the development of the criminal trial, to have in its possession material, exculpatory evidence that is unavailable to the defense. Although the CBS material in the district court’s possession has not been made available to the prosecution and thus might be more correctly characterized as information from a neutral third party discovered after trial, see Agurs, 427 U.S. at 111 & n. 10, 96 S.Ct. at 2401 & n. 10, 1 will refer to the district court’s alleged obligation to disclose such material as a Brady -type obligation and will assume for purposes of this appeal that the court may be subjected to the same standard as the prosecution.
. Further, I recognize that because of this difficulty a prudent prosecutor will voluntarily resolve any doubts in favor of disclosure, and a district court, viewing the government’s material in camera to determine whether it should be produced to the defense, might do the same. However, when a district court views nonpro-secutorial material in camera, if the defendant is powerless to obtain such material directly from the person opposing disclosure, I believe that the court should disclose such material, if at all, only when the Constitution clearly compels it to do so.
. I also agree with the majority that it is not necessary to reach the merits of the petitions for writ of mandamus in Nos. 81-1470, -1485.