Prosecutors are required by law to disclose any evidence that tends to exonerate or exculpate you from criminal charges which could help demonstrate your actual innocence or that could reduce your sentence to you and your defense counsel. Called "Brady material," this requirement means that prosecutors must disclose evidence known only to police, agreements relating to witness testimony and any other information that tends to show you may not be guilty. Failures to disclose this and other misconduct by the prosecutor may be the basis for appeal or other post-conviction/post-judgment relief.
Impeachable Testimony: Brady v. Maryland, 373 U.S. 83 (1963)In 1963, the state of Maryland prosecuted John L.Brady and a companion, Mr. Boblit, for murder. Brady admitted being involved in the murder, but claimed Boblit had done the actual killing. The prosecution had actually withheld a written statement by Boblit confessing that he had committed the act of killing by himself and the defendant challenged his conviction, arguing it had been contrary to the Due Process Clause of the Fourteenth Amendment to the United States Constitution.
The Supreme Court held that withholding exculpatory evidence violates due process "where the evidence is material either to guilt or to punishment"; and the court determined that under Maryland state law the withheld evidence could not have exculpated the defendant but was material to the level of punishment he would be given. Hence the Maryland Court of Appeals' ruling was affirmed.
Because of the Brady ruling, prosecutors are required to notify defendants and their attorneys whenever a law enforcement official involved in their case has a confirmed record of knowingly lying in an official capacity. Brady evidence also includes evidence material to credibility of a civilian witness, such as evidence of false statements by the witness or evidence that a witness was paid to act as an informant.
Frequently, prosecutorial misconduct is not apparent during trial proceedings; knowledge of misconduct may surface only after a trial has ended. Like all appellate or post-conviction/post-judgment litigation, appeals or collateral challenges based on prosecutorial misconduct involve complex rules and procedures.