How Does a Grand Jury Work?

In the United States a grand jury is a group of 16 to 23 people chosen by a court for the purpose of determining whether a person suspected of having committed a crime may be indicted. Prosecutors present the grand jury with evidence of the suspect’s alleged criminal activity, and the jury usually obtains additional evidence through requested witness testimony and subpoenaed records. The grand jury then takes a vote on the question of whether there is probable cause or prima facie evidence to believe that the suspect did in fact commit the crime. If the jury so finds, the case proceeds to trial in which a “petit jury” of six or 12 members decides whether the suspect’s guilt is “beyond a reasonable doubt.” If the petit jury so finds, the suspect is convicted and usually sentenced to imprisonment or (in some capital cases) to death. Although alleged violations of criminal law are considered by both federal and state grand juries, some states have a distinct group of grand juries concerned with civil law violations.

The Fifth Amendment to the U.S. Constitution guarantees (with only a few exceptions) that “[n]o person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a Grand Jury.” As interpreted by the U.S. Supreme Court, the amendment applies to federal but not to state prosecutions, and the right to indictment can be waived by people accused of serious but not capital crimes (see capital punishment).

Step 1

A court agrees to allow a prosecutor or team of prosecutors to pursue an indictment of a person suspected of a capital crime or a felony punishable by imprisonment of at least one year. From a randomly selected panel of registered voters, the court chooses 16–23 people who are then informed of their function and introduced to details of the case. The grand jury usually has a foreperson elected from its members or appointed by the court.

Step 2

Prosecutors present the grand jury with evidence supporting criminal charges against the suspect. The jury also considers information obtained from its own investigations, which may include witness testimony and subpoenaed documents. The jury does not hear arguments from defense attorneys, and the judge who selects the jury does not usually attend its hearings. The hearings are normally conducted in secret to protect witnesses and to avoid damaging the reputations of suspects who are not indicted.

Step 3

When the grand jury is ready to make a decision, it takes a vote on the question of whether there are reasonable grounds for believing that the suspect is guilty. If at least 12 members (or, in some jurisdictions, two-thirds or three-quarters of the jurors) find reasonable grounds, the suspect is indicted. If the jury does not find such grounds, no indictment is issued and prosecutors usually drop the case. Although prosecutors may still take the suspect to trial, a guilty verdict in that event is usually more difficult to obtain.