Grand jury

A grand jury is a judicial body, typically having twenty-three or more members, that serves as a group for a sustained period of time in all or many of the cases that come up in a jurisdiction, generally under the supervision of a federal U.S. attorney, a county district attorney, or a state attorney-general and hears evidence ex parte (i.e. without suspect or person of interest involvement in the proceedings).

Rule 6 of the Federal Rules of Criminal Procedure requires grand juries to include 16 to 23 members. Twelve members of a grand jury must concur in an indictment. A grand jury is instructed to return an indictment if the probable cause standard has been met. The grand jury's decision is either a "true bill" (formerly billa vera, resulting in an "indictment"), or "no true bill". Grand jury proceedings are secret; no judge is present, and the proceedings are led by a prosecutor.

The term comes from the Fifth Amendment to the United States Constitution, which states that "No person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a Grand Jury, except in cases arising in the land or naval forces, or in the Militia, when in actual service in time of War or public danger."