The Federal Bureau of Investigation To uphold the law through the investigation of violations of federal criminal law; to protect the U.S. from foreign intelligence and terrorist activities; to provide leadership and law enforcement assistance to federal, state, local, and international agencies; and to perform these responsibilities in a manner that is responsive to the needs of the public and is faithful to the constitution of the U.S.: this is the mission of the Federal Bureau of Investigation. The agency now known as the Federa