Under Brady v. Maryland, 373 U.S. 83 (1963), the prosecution has a duty to disclose exculpatory or impeaching evidence to a criminal defendant. Prosecutors’ violation of this Brady duty can be the basis for arguments both by defendants/appellants in criminal cases and by plaintiffs bringing civil rights claims under 42 U.S.C. § 1983.
To establish a Brady claim, a plaintiff must prove: (1) the withheld evidence was favorable either because it was exculpatory or could be used to impeach, (2) the evidence was suppressed by the government, and (3) the nondisclosure prejudiced the plaintiff. Smith v. Almada, 640 F.3d 931, 939 (9th Cir. 2011). A showing of prejudice requires demonstrating a “reasonable probability” of a more favorable outcome.