By Kan Nawaday (March 19, 2018, 1:11 PM EDT) -- For criminal defendants and their counsel, obtaining material that undercuts the credibility of a government cooperating witness is imperative. In that regard, use of Federal Rule of Criminal Procedure Rule 17(c) subpoenas to identify and obtain damaging materials from nonparties about cooperating witnesses has always been de rigueur for the criminal defense bar. For example, in the trial of United States v. Campo Flores, et al.,[1] defense counsel obtained, through a Rule 17 subpoena, prison calls of the government's cooperating witness during which the witness discussed dealing drugs after he had entered into a cooperation agreement with the government. Confronted with these recordings, the cooperating witness admitted to violating the terms of his agreement on cross-examination, undoubtedly leading the prosecutors to threaten to "rip up" the witness' cooperation agreement on redirect examination....