Reversal and remand were required where the prosecution failed to disclose exculpatory evidence in violation of Brady v. Maryland (1963) 373 U.S. 83. The evidence which was not disclosed until a year after trial was that a main prosecution witness could not identify a photograph of the victim, a fact which could have been helpful to the defense, and undercut the prosecution’s theory of the case. Brady is not confined to evidence that affirmatively proves a defendant innocent; it applies where, as here, the evidence was favorable to the accused. The state’s case was weak, and it was reasonably probable that there would have been a different result if the evidence had been disclosed. Remand was required so that the district court could hold an evidentiary hearing.