The defendant’s motion for new trial based on the government’s non-disclosure of the informant’s prior convictions, a prior false crime report made by her, and defense counsel’s failure to locate this information through his own efforts, was properly denied. In federal prosecutions, evidence that merely impeaches a witness does not support a new trial motion. Also, because the evidence presented in the case also included identifications by two other eyewitnesses and by photographs taken by the camera in the bank, any error of counsel was not prejudicial within the meaning of Strickland v. Washington (1984) 466 U.S. 668, 694.