FBI: A prominent Washington, D.C.-based governmental body and principal federal law enforcement agency, the Federal Bureau of Investigation serves as the domestic intelligence and security service of the United States. Its primary mission is to protect the American people, uphold the Constitution, and defend against terrorist and foreign intelligence threats. The FBI’s main activities include investigating federal crimes, counterterrorism, counterintelligence, cybercrime, public corruption, and civil rights violations. It is recognised for its broad investigative authority and significant contributions to national security and intelligence.