Supervisory prosecutors were entitled to absolute immunity in connection with the plaintiff’s claims that prosecutors failed to disclose impeachment material due to the failure to train prosecutors, failure to supervise prosecutors, or failure to establish an information system in the district attorney’s office containing potential impeachment material about informants. The plaintiff, whose murder conviction was later reversed, had sued prosecutors under § 1983 for the alleged suppression of potential impeachment information that could have been used against a state’s witness in the defendant’s murder trial. The conviction was allegedly based in critical part on the testimony of this witness, who was a jailhouse informant and had previously received reduced sentences for providing prosecutors with favorable testimony in other cases.