Synonyms and related words :
Bow Street runner, FBI, FBI agent, Federal, G-man, Secret Service, Sherlock, T-man, detective, dick, eye, fed, gumshoe, hawkshaw, hotel detective, house detective, house dick, inquiry agent, investigator, narc, operative, plainclothesman, police detective, private detective, private investigator, revenuer, sleuth, store detective, tec, treasury agent