Definitions for "Federal Bureau of Investigation"
A federal agency which investigates all violations of federal laws.
a federal law enforcement agency that is the principal investigative arm of the Department of Justice
The principal investigative arm of the United States Department of Justice. The mission of the FBI is to uphold the law through the investigation of violations of federal criminal law; to protect the United States 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 United States.