A detective is an investigator, either a member of a police agency or a private person. Private detectives usually operate commercially and are licensed. They may be known as private investigators (P.I.s or "private eyes"). Informally, and primarily in fiction, a detective is any licensed or unlicensed person who solves crimes, including historical crimes, or looks into records. The origins of the slang term "gumshoe" are believed to be from the etymological implications of the need of detectives to get down and dirty during the course of their investigations