A grand jury is made up of a group of citizens, typically 16 to 23 members in federal cases, selected from the community where the grand jury is located. These members are usually chosen randomly from lists of registered voters or similar sources and are meant to represent a broad cross-section of the population, considering factors such as race, sex, and age. The grand jury is responsible for investigating potential criminal conduct and determining whether there is probable cause to bring criminal charges. It does not decide guilt or innocence but decides if there is enough evidence for an indictment. The jury is overseen by a foreperson chosen from among its members, and its proceedings are conducted in secret to protect the integrity of the process.