Grand jury

A grand jury is a group of citizens, typically 16 to 23, who hear evidence presented by a prosecutor to decide whether there is probable cause to believe a person committed a crime. If they agree, they return an "indictment," a formal charge. The Fifth Amendment requires a grand-jury indictment for federal felony prosecutions, though it has not been applied to the states, many of which use other procedures such as preliminary hearings.

Proceedings are secret, and neither the defendant nor defense counsel usually appears. The panel can issue subpoenas for documents and testimony and can investigate possible wrongdoing. The standard of proof is far lower than the "beyond a reasonable doubt" needed to convict, which led to the saying that a prosecutor could persuade a grand jury to "indict a ham sandwich."

Supporters see the grand jury as a community check on prosecutors, as when juries decline to indict. Critics say it is dominated by prosecutors and rarely refuses them. Special or investigative grand juries, and a separate "grand jury report" power in some states, have been used in high-profile political and corruption inquiries. Compare the oversight powers of Congress such as the congressional subpoena, and the protection against a second prosecution under double jeopardy.