The grand jury plays an important role in the criminal process, but not one that involves a finding of guilt or punishment of a party. Instead, a prosecutor will work with a grand jury to decide whether to bring criminal charges or an indictment against a potential defendant -- usually reserved for serious felonies. Grand jury members may be called for jury duty for months at a time, but need only appear in court for a few days out of every month. Regular court trial juries are usually 6 or 12 people, but in the federal system, a grand jury can be 16 to 23 people.
The grand jury is one of the first procedures in a criminal trial, if used at all. See FindLaw's Criminal Procedure section for more articles, including Criminal Procedure FAQ and How are Criminal Charges Brought Against Someone?
How Does a Grand Jury Differ from a Preliminary Hearing?
While all states have provisions in their laws that allow for grand juries, roughly half of the states don't use them. Courts often use preliminary hearings prior to criminal trials, instead of grand juries, which are adversarial in nature. As with grand juries, preliminary hearings are meant to determine whether there is enough evidence, or probable cause, to indict a criminal suspect.
Unlike a grand jury, a preliminary hearing is usually open to the public and involves lawyers and a judge (not so with grand juries, other than the prosecutor). Sometimes, a preliminary hearing precedes a grand jury. One of the biggest differences between the two is the requirement that a defendant request a preliminary hearing, although the court may decline a request.
Grand Jury Proceedings
Grand jury proceedings are much more relaxed than normal court room proceedings. There is no judge present and frequently there are no lawyers except for the prosecutor. The prosecutor will explain the law to the jury and work with them to gather evidence and hear testimony. Under normal courtroom rules of evidence, exhibits and other testimony must adhere to strict rules before admission. However, a grand jury has broad power to see and hear almost anything they would like.
However, unlike the vast majority of trials, grand jury proceedings are kept in strict confidence. This serves two purposes:
The Grand Jury's Decision and a Prosecutor's Discretion
Grand juries do not need a unanimous decision from all members to indict, but it does need a supermajority of 2/3 or 3/4 agreement for an indictment (depending on the jurisdiction). Even though a grand jury may not choose to indict, a prosecutor may still bring the defendant to trial if she thinks she has a strong enough case. However, the grand jury proceedings are often a valuable test run for prosecutors in making the decision to bring the case.
If the grand jury chooses to indict, the trial will most likely begin faster. Without a grand jury indictment, the prosecutor has to demonstrate to the trial judge that she has enough evidence to continue with the case. However, with a grand jury indictment, the prosecutor can skip that step and proceed directly to trial.
If you have more questions about how a grand jury works, or need help with a criminal case, consider speaking with a criminal defense lawyer in your area.