In United States v. Bernal-Obeso, 989 F.2d 331 (9th Cir. 1993), the court reversed the appellant's conviction and remanded the case for an evidentiary hearing, after determining that "a material lie by a critical informant-witness about his prior record would be exculpatory and thus discoverable Brady information which the government would be under a Constitutional duty to disclose." Id. at 336. The court recognized: "By definition, criminal informants are cut from untrustworthy cloth and must be managed and carefully watched by the government and the courts to prevent them from falsely accusing the innocent, from manufacturing evidence against those under suspicion of crime, and from lying under oath in the courtroom." Id. at 333. The Ninth Circuit further explained: By its actions, the government can either contribute to or eliminate the problem. Accordingly, we expect prosecutors and investigators to take all reasonable measures to safeguard the system against treachery. This responsibility includes the duty as required by Giglio v. United States, 405 U.S. 150 (1972) to turn over to the defense in discovery all material information casting a shadow on a government witness's credibility. Id. at 334.