A Grand Jury is a legal body composed of citizens that reviews evidence presented by a prosecutor to determine whether there is enough evidence to charge someone with a crime. Unlike a trial jury, which decides guilt or innocence, a grand jury's role is to decide if there is probable cause to proceed with criminal charges. Grand juries typically consist of 16 to 23 members and operate in secrecy to protect the privacy of those involved. Their proceedings can lead to an indictment, which formally charges a person with a crime, allowing the case to move forward in the judicial system.