Someone who’s been formally accused of a crime is normally entitled to certain kinds of evidence and information. In general, a defendant has a right to receive this kind of material, called “discovery,” before trial. But the prosecution’s duty to hand over discovery is usually ongoing—it doesn’t end merely because a trial has begun.

Types of Discovery

A police report is a common example of discovery. (However, the law might not require disclosure of police reports in all states.) A typical one will contain the names of any victims or witnesses, reports of statements by such people, observations by the officer, and more. The police report is sometimes the first item of discovery that a defense attorney receives.

Other forms of discovery include—but certainly aren’t limited to—

• recordings of police interviews of victims, witnesses, and defendants
• photographs of alleged crime scenes and the people involved in the events in question, and
• records—for instance, police personnel records, medical records relating to injuries, and witnesses’ criminal records.

The Right to Discovery: Brady Material

Courts have held that the U.S. Constitution doesn’t impose a general duty on the prosecution to disclose “material” evidence to the defense. “Material” is generally shorthand for “relevant”; it’s often used to refer to evidence that, if disclosed, could affect the outcome of a case.

Exculpatory Evidence

The Constitution does, however, require that the prosecution disclose to the defense exculpatory evidence within its possession or control. “Exculpatory” generally means evidence that tends to contradict the defendant’s supposed guilt or that supports lesser punishment. The evidence doesn’t have to strongly indicate innocence in the way that an alibi, for example, would. It’s generally enough that the evidence provides significant aid to the defendant’s case. So, information that affects the credibility of a critical prosecution witness—like the fact that the prosecution offered its witness leniency in exchange for testimony—is among the kinds of evidence prosecutors have disclose. (Giglio v. United States, 405 U.S. 150 (1972).)

Defense attorneys routinely submit requests for discovery, and they make sure to ask for the above evidence, which often goes by “Brady material.” The government violates the law by not turning over this kind evidence, even if the failure to disclose wasn’t intentional or was beyond the prosecution’s control.

Brady Violations

If the defense learns about a Brady violation after the defendant has been convicted, the defendant is typically owed a new trial if the nondisclosure was material. According to the U.S. Supreme Court, the missing evidence is to be considered as a whole rather than piece by piece, but it’s material only if there’s a “reasonable probability that, had the evidence been disclosed to the defense, the result of the proceeding would have been different.” (United States v. Bagley, 473 U.S. 667 (1985); Kyles v. Whitley, 514 U.S. 419 (1995).)

Courts have tended to be quicker to find Brady violations where the defense has specifically requested an item and the prosecution has misled the defense about its existence. Courts will find Brady violations in other circumstances too, as when the defense has made a very general request for exculpatory material or hasn’t made any request. But they might be slower to hold that the omission was material in these kinds of situations.

Federal and State Discovery Statutes

Brady and the cases related to it provide what’s essentially a baseline for what prosecutors have to turn over to the defense. The federal system and many states have statutes that entitle the defense to more material. (Sometimes the defense must request this material.)

Federal and state statutes often require disclosure of items like the following:

• statements by the defendant and any co-defendants
• documents and tangible objects the prosecution will use at trial
• a list of the witnesses the prosecution plans to have testify at trial (and perhaps prior statements by those witnesses)
• copies of reports of scientific tests and medical and physical examinations that have been prepared for the prosecution

Here’s an example of a discovery law, from California:

Questions for Your Attorney

• What are the procedures for obtaining discovery in my case?
• How does the defense get discovery from a third party (someone or some entity other than the prosecution)?
• When in the proceedings does the prosecution have to provide discovery?
• What happens when evidence that should be disclosed is lost or destroyed?
• Does anything else, like ethics rules or the state constitution, require that the prosecution disclose more material?
• Are depositions allowed in my jurisdiction?
• What remedies are available in my jurisdiction if the prosecution violates its discovery duties?
• What kind of discovery does the defense have to provide the prosecution?