Any evidence held by the State that could help or harm the defendant's case must be shown to the defendant or his lawyer. In both civil and criminal cases, discovery involves investigating the evidence that the other party plans to present. It can avoid surprises at trial, reduce the issues being discussed, and often help both parties reach a resolution out of court rather than having to go through a full trial. In the criminal context, discovery usually consisted mainly of the accused obtaining evidence from the prosecution.
This could include reports and records made by the police, as well as the statements of witnesses who will testify on behalf of the prosecution. However, this has changed in the modern era, allowing the prosecution to obtain some types of evidence from the defense. The discovery allows the parties to know before the trial begins what evidence can be presented. It is designed to avoid an ambush trial, in which one party doesn't learn about the other party's evidence or witnesses until the trial, when there is no time to obtain evidence to respond.
If you're involved in a federal criminal case, make sure your lawyer is familiar with how the federal criminal investigation works, or you could overlook important information that could help you win your case. The discovery of federal crimes can be a complex field to explore, and sometimes local practices may not meet the letter of the regulations. The justification for a more limited right of discovery in criminal cases is that the government cannot force the accused to present evidence against them, so the accused must have limits on what they can discover from the government. Therefore, it is critical that an attorney in a federal criminal case make good use of these three sources and ensure that they obtain the maximum amount of information from each of them.
While this more limited right of discovery in criminal cases may seem “fair” in light of the defendant's right not to incriminate himself, in practice limited discovery often results in an unjust surprise at trial or, worse, in the conviction of innocent defendants. Rule 16 of the Federal Rules of Criminal Procedure is the main source of law governing discovery in federal criminal cases. Nearly all criminal cases end up in settlements with the prosecution, and the transparency of the discovery process is likely part of the explanation.
