G-Man (slang) G-Man (slang) G-Man (short for "Government Man") is an American slang term for special agents of the United States Government. It is specifically used as a term for a Federal Bureau of Investigation (FBI) agent. "G-Man" is also a term used for members of G Division, essentially a British anti-rebel police unit operating out of Dublin Castle prior to Irish Independence in 1922. Colonel Ned Broy uses the term in his official testimony for the Irish Army's Bureau of Military History in their archive of the Easter Rising (1916) and the Irish War of Independence (1919-1921). According to the "Merriam-Webster
Leon G. Turrou nation against espionage. During his investigation, Turrou used polygraph tests to interview his suspects, perhaps the first of its use by the FBI in an espionage investigation. The subjects of his investigation were Martin Schade, Captain William Drechsel, Karl Friedrich Wilhelm Herrmann, John Baptiste Unkel, Kate Moog and Dr. Ignatz T. Griebl. Turrou's newspaper articles were used as the basis of the film, "Confessions of a Nazi Spy". Leon G. Turrou Leon George Turrou (September 14, 1895 - December 10, 1986) was an FBI Special Agent who was tasked with leading an investigation that located and interrogated Nazi German spies