Prosecutors have a constitutional mandate to disclose exculpatory evidence to defendants in criminal cases. The failure to disclose evidence favorable to an accused “violates due process where the evidence is material either to guilt or to punishment, irrespective of the good faith or bad faith of the prosecution.” The Brady rule imposes on the prosecution a constitutional duty to volunteer exculpatory matter to the defense “even in the absence of a request therefor.”
Independent from discovery statutes: The constitutional duties of the prosecutor operate independently from the California criminal discovery statutes. “The prosecutor’s duties of disclosure under the due process clause are wholly independent of any statutory scheme of reciprocal discovery. The due process requirements are self-executing and need no statutory support to be effective.” The discovery statutes recognize that discovery must occur if “mandated by the Constitution of the United States.” California Penal Code § 1054(e)).
Brady violation: In the landmark case of Brady v. Maryland, 373 U.S. 83, 87, 83 S. Ct. 1194, 10 L. Ed. 2d 215 (1963), the United States Supreme Court held that “the suppression by the prosecution of evidence favorable to an accused upon request violates due process where the evidence is material either to guilt or punishment, irrespective of the good faith or bad faith of the prosecution.” Thus, there are three essential components of a Brady violation: (1) the evidence at issue must be favorable to the accused, either because it is exculpatory or because it is impeaching; (2) that evidence must have been suppressed by the prosecution, either willfully or inadvertently; and (3) the evidence must be “material”, that is, prejudice must have resulted.