A Grand Jury does not determine guilt or innocence, but whether there is probable cause to believe that a crime has been committed. The evidence is normally presented only by an attorney for the government. The grand jury must determine from this evidence whether a person should have formal charges filed by the government. If the grand jury finds probable cause, then it will return a written statement of the charges, called an indictment. Grand jurors are on a panel of 23 jurors and generally serve one to two days per month for 18 months. Grand jury terms may be extended for 6 months if necessary.