The prosecution has to divulge evidence that’s favorable to the defense—even if the defense doesn’t ask for it.
As part of their obligation to pursue justice and promote fairness, prosecutors have a duty to reveal “favorable” information to the defense, as explained below.
For information on discovery law generally, see What and When the Prosecution Must Disclose. For information on trying to make sure the prosecution turns over favorable information, see How can I find out if the prosecution is hiding helpful evidence?
Prosecutors have to provide defendants with favorable information, which includes exculpatory and impeachment evidence.
Information is exculpatory if it is known to the prosecution and tends to prove that a defendant isn’t guilty. (Brady v. Maryland, 373 U.S. 83 (1963).) It must be “material”—that is, likely to have changed a trial’s outcome had the prosecution disclosed it.
Information qualifies as impeachment evidence if it tends to discredit a prosecution witness. For example, prosecutors have to turn over to defendants:
- a prosecutor’s promise of leniency to a witness in exchange for the witness’s testimony, and
- a prosecution witness’s previous conviction of a crime that a defendant could offer into evidence to attack the witness’s credibility.
However, the government doesn’t have to disclose impeachment information prior to entering plea agreement with a defendant. (United States v. Ruiz, 536 U.S. 622 (2002).)
How Helpful Is “Helpful”?
To qualify as exculpatory, information doesn’t have to be so powerful that it proves the defendant conclusively innocent. As long as information known to the prosecution might contribute to doubt about the defendant’s guilt in the mind of a reasonable person, the prosecutor must reveal it.
EXAMPLES OF THE DUTY TO DISCLOSE
EXAMPLE 1: Maso Menos is charged with burglary. Two witnesses who saw Menos in a lineup identified him as the burglar. However, a third witness present at the same lineup stated that Menos wasn’t the burglar. The prosecutor doesn’t think that the third witness is telling the truth. Nevertheless, the prosecutor has to tell Menos about the third witness. It’s not up to the prosecutor to decide who’s telling the truth and who isn’t. Information about the third witness is potentially helpful to Menos, so the prosecutor has to disclose it.
EXAMPLE 2: Mai O’Mai’s conviction of a serious felony rested largely on the identification testimony of a single prosecution eyewitness. After the trial, O’Mai finds out that the prosecution failed to turn over two statements in which the eyewitness told the police before trial that he didn’t see any faces and would be unable to identify the culprit. The exculpatory statements were material because there’s a reasonable probability that their disclosure would have changed the trial’s outcome. O’Mai’s conviction should be reversed. (Smith v. Cain, 132 S. Ct. 627 (2012).)
EXAMPLE 3: Jane Austere is on trial for robbery of a small market. Her defense is mistaken identity. The prosecution’s primary witness is Al Cohol, who identifies Jane as the robber. Jane is convicted. Jane then learns that the prosecutor knew prior to trial—but failed to tell her—that Cohol had undergone years of treatment for alcohol addiction. Jane asks the judge to set aside the conviction and order a new trial because of the prosecution’s failure to turn over this information. The prosecutor asks the judge to deny the request because Jane never specifically asked for information concerning Cohol’s background. The judge should order a new trial: The information is important because Cohol’s years of alcohol abuse might case doubt on his ability to identify Jane. Prosecutors have to disclose important favorable information even if the defendant fails to ask for it. After all, how can you ask for it if you don’t know it exists?
Consequences of Failing to Disclose
If a prosecutor fails to turn over significant favorable information and the defendant is convicted, an appellate court can overturn the conviction. However, prosecutors are totally immune from personal liability if they don’t turn over favorable evidence to the defense. (Van de Kamp v. Goldstein, 555 U.S. 335 (2009).) This means that defendants who have been convicted and imprisoned due to a prosecutor’s failure to disclose information can’t sue the prosecutor in civil court.