There are a few purposes of a grand jury. The main reason for having a grand jury is to make sure that there will be a fair trial.
Depending on the state you are in (some use the Grand Jury System and others use the Preliminary Hearing system) it is the hearing at which the defendant is formally charged with the offense he was arrested for.
The Athenian jury system selected jurors randomly from a pool of volunteers, while the US jury system selects jurors from voter registration or drivers license lists. In Athens, the jury size could be up to 501 citizens, while in the US, a standard jury size is 12. Additionally, in Athens, jurors voted by placing a token in one of two urns, whereas in the US, jurors deliberate and reach a consensus verdict.
YOU (individually) don't NEED and can't request, a Grand Jury. Grand Juries are convened at the direction of the government, not at the request of the defendant. A grand jury decides if there is enough evidence to stand trial.
The grand jury reviews the evidence against the accused
Generally all felony offenses. CAUTION: Not all states indict defendants via the Grand Jury system.
Grand Jury Inquiry
Wayne L. Morse has written: 'Visit to Japan, India, Pakistan, Afghanistan, and Israel' -- subject(s): Foreign relations, Politics and government 'A survey of the grand jury system' -- subject(s): Grand jury
If the jurisdiction in question adheres to the Grand Jury system of indictment, the GJ will indict by handing down a "true bill" in the sequence in which it was presented to them. HOWEVER - if the jurisdictions NOT utilizing a Grand Jury system, your Preliminary Hearing IS your idndictiment and the presiding judge decides if there is enough Probable Cause to bind you over for trial.
More information is needed - some states do not use the Grand Jury system to indict you of an offense.
The grand jury listens to all the evidence in a case against the accused and decides whether to charge the individual with the crime. This is called an indictment or an information.
In states which do not use the Grand Jury system there is no "indictment," the defendant is simply "formally charged" with the offense by the prosecutor. .
Grand juries and Petit juries are the two kinds of juries. Grand juries review evidence of criminal action to determine if there is probable cause for bringing charges and if so, issue an indictment. Petit juries review evidence in both civil and criminal trials to determine the facts and render verdicts either for or against the parties in civil actions or guilty or not guilty in criminal actions.