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Before a prosecutor begins a trial, there is much work to be done. The prosecutor has to become familiar with the facts of the crime, talk to the witnesses, study the evidence, anticipate problems that could arise during trial, and develop a trial strategy. The prosecutor may even practice certain statements they will say during trial.

Meanwhile, the defense attorney is preparing in the same way.

One of the first steps in preparing for trial is talking to witnesses who could be called to testify in court. A witness is a person who saw or heard the crime take place or may have important information about the crime or the defendant.

Both the defense and the prosecutor can call witnesses to testify or tell what they know about the situation. What the witness actually says in court is called testimony. In court, the witness is called to sit near the judge on the witness stand. In order to testify, witnesses must take an oath to agree or affirm to tell the truth.

There are three types of witnesses:

  • A lay witness — the most common type — is a person who watched certain events and describes what they saw.
  • An expert witness is a specialist — someone who is educated in a certain area. They testify with respect to their specialty area only.
  • A character witness is someone who knew the victim, the defendant, or other people involved in the case. Character witnesses usually don’t see the crime take place but they can be very helpful in a case because they know the personality of the defendant or victim, or what type of person the defendant or victim was before the crime. Neighbors, friends, family, and clergy are often used as character witnesses.

To avoid surprises at trial and to determine which of the witnesses to call to testify, the prosecutor talks to each witness to find out what they may say during trial. These conversations will help the prosecutor decide whom to call as a witness in court.

Another important part of trial preparation is reading every report written about the case. Based on information in the reports and the information from witnesses, the prosecutor determines the facts of the case.

Prosecutors must also provide the defendant copies of materials and evidence that the prosecution intends to use at trial. This process is called discovery, and continues from the time the case begins to the time of trial. A prosecutor has a continuing obligation to provide the defendant documents and other information which may reflect upon the case. A failure of the prosecutor to do so can expose the prosecutor to fines/sanctions by the court. Further, the prosecutor is required to provide the defense with evidence that may hurt his case, called exculpatory evidence. This evidence could show the defendant’s innocence. If the prosecution does not provide it to the defense, it may require a new trial.