A grand jury is a sworn body of citizens (jurors) who are authorized by law to engage in certain legal proceedings. Most grand juries are convened to investigate violations of criminal law, though civil grand juries are occasionally called, most often to investigate government misconduct. Grand juries may be convened in either a state or federal court.
Pursuant to the terms of the 5th Amendment to the U.S. Constitution, the federal government must use a grand jury when considering any felony charge. About half of the states mandate grand jury proceedings for felonies.
A grand jury proceeding looks very much like a trial, except that defense attorneys are not present and no one argues on behalf of the accused. The task of the grand jury is to determine whether there is sufficient evidence to charge a person with a criminal act. Typically, the prosecutor will make arguments and present evidence of potential criminal violations. Witnesses are often called as part of the process. Once the evidence and arguments have been presented to the grand jury, the jury determines only whether there is enough evidence to formally charge the accused and initiate a prosecution. If so, the grand jury will issue an indictment.
When law enforcement officers complete a criminal investigation, they give all the evidence they’ve obtained to the prosecutor’s office. The prosecutor will indicate to the court that a grand jury is required, and the court will pull together lists of potential jurors (from voter registration rolls or other sources) and summon the potential jurors to appear on a specific date. Potential jurors may ask to be excused but may only duty only at the discretion of the court. Prosecutors generally do not screen potential grand jury members for bias but only to ensure that there are no language barriers and that they have not been convicted of any felonies.
Federal grand juries are typically composed of 16-23 jurors. Depending on the nature of the charges, grand jury duty may last as long as 18 months. In the federal courts, grand jurors are compensated $50 per day and can seek reimbursement for most transportation expenses. The length of duty and amount of compensation varies in state courts.
A vote to indict indicates only that the grand jury believes there is sufficient evidence to bring formal charges against a potential defendant. The grand jury makes no determination with respect to guilt or innocence.
When the grand jury decides not to indict, it’s commonly referred to as a “no bill.” In most instances, prosecutors will choose not to move forward with criminal charges in a “no bill” case, but there’s no requirement that charges be dropped or the prosecution terminated.
In the absence of an indictment, prosecutors in some jurisdictions may file what is commonly referred to as an “information” or “bill of information.” The defendant may still face prosecution but the prosecutor will need to show probable cause as to why the prosecution is moving forward.