The U.S. Department of Justice, through its 93 U.S. Attorneys’ offices throughout the country, is tasked with investigating and prosecuting violations of federal law. Citizens within the geographic boundaries of their respective U.S. Attorney’s office are selected to serve a term on a federal grand jury. Those citizen servants make up the grand jury and are tasked with deciding whether a person subject to a grand jury investigation violated a federal statute(s).
The U.S. Attorney’s office applies for authorization to present evidence to a grand jury. Once given that authorization by the District Court, the prosecutor assigned to the investigation has almost unbridled discretion to subpoena witnesses, obtain records, assigned FBI agents to investigate potential coconspirators and gather any information they believe is relevant to their investigation.