In both civil and criminal cases, discovery involves investigating the evidence that the other side plans to present. It can prevent any surprises at trial, narrow the issues that are disputed, and often help the two sides reach a resolution out of court rather than going through a full trial. In the criminal context, discovery once consisted mostly of the defendant getting evidence from the prosecution. This might include the reports and records made by the police, as well as statements by witnesses who will testify for the prosecution. (Read more here about interviewing prosecution witnesses.) However, this has changed in the modern era, allowing the prosecution to get some types of evidence from the defense.

Avoiding an Ambush at Trial

You may have seen TV shows or read novels in which trials are decided by a shocking twist when one side or the other reveals a surprise witness or document. Historically, this could happen because prosecutors were not required to share their evidence with defendants. Modern conceptions of fairness have changed this rule and recognized the importance of allowing defendants and their attorneys to craft the strongest defense available. Sharing the prosecution’s evidence also levels the playing field between the vast resources at the disposal of the government and the limited resources available to a defendant. Discovery rules apply at both state and federal levels.

That said, the prosecution does not need to offer a completely open book to the defense. Prosecutors do not need to share their theory of the case with the defendant’s attorney, nor do they need to provide them with notes taken about the case. These are protected by the work product rule, which covers an attorney’s impressions, observations, and subjective thoughts about a case. Discovery is limited to objective types of information, such as police records, scientific evidence, and witness lists and statements, as discussed above.

The Impact of Discovery

You might think that discovery increases the chance that a defendant will win at trial, but this is not necessarily true. Often, knowing more about the strengths of the prosecution’s case will encourage a defendant to accept a plea bargain rather than taking their case to a jury. This can further the efficiency goals of the prosecution and secure a conviction for the prosecutor, which is usually viewed as a successful result. Almost all criminal cases end in plea bargains, and the transparency of the discovery process probably forms part of the explanation. Therefore, discovery can help both defendants and prosecutors.

Timing in the Discovery Process

There are very few rules that govern the timing of discovery. Notions of fairness prevent the prosecution from dumping all of the relevant information on the defense just before trial, but they do not need to disclose all of it immediately. Sometimes the prosecution might disclose certain items, such as the police report of the incident leading to the arrest, before certain other items, such as forensic analysis. Witness lists may not be developed until the prosecution has spent some time developing the case, and they may change over time. Unless a case is very simple, discovery is usually an ongoing exchange rather than a single transfer of information.

Getting Police Personnel Records

Often, the prosecution’s case rests heavily on the testimony of the arresting officer. Most jurors will trust the testimony of an officer over the testimony of other witnesses, and they often assume that the officer handled a situation appropriately. If part of the defense involves a claim that the police mishandled the situation, the defendant’s attorney may want to get the officer’s personnel records. This will contain any history of misconduct or complaints by people who interacted with the officer. The defense then might follow up on any leads and interview potential witnesses who could testify about the officer’s previous behavior.

The government does not need to hand over these files to the defense if they will not be relevant to the defendant’s case. Usually, the appropriate agency will conduct a review of a file and give the defense only the parts of the file that may be relevant. A court may need to intervene if any dispute arises over whether and how much of the file should be shared with the defense.

Last updated May 2019