In United States v. Acevedo-Ramos, 755 F.2d 203 (1st Cir.1985), a federal agent had given detailed hearsay testimony - based on undisclosed informant reports and wiretap intercepts - implicating the defendant in eight specific crimes, including murders, armed robberies, and obstruction of justice. See United States v. Acevedo-Ramos, 755 F.2d at 205. Rejecting the defendant's hearsay challenge to this evidence, then Circuit Judge Breyer, writing for the panel, noted that a district court's "sensible exercise" of its power "selectively to insist upon the production of the underlying evidence or evidentiary sources" adequately protected a "defendant's right to cross-examine without unnecessarily transforming the bail hearing into a full-fledged trial or... discovery expedition." Id. at 207-08. Judge Breyer then added the observation relied on by the government in this case: Even in an unusual case, where the government provides strong special reasons for keeping its evidentiary sources confidential (e.g., protecting witness safety), the magistrate or judge, upon defendant's request, can still test the veracity of the government's testimony and the quality of the underlying evidence, by, for example, listening to tapes or reading documents in camera. Id. at 208.