I think you mean the Secret Service started out as the Pinkerton Detective Agency. They became part of the government due in part of protecting the president an

I think you mean the Secret Service started out as the Pinkerton Detective Agency. They became part of the government due in part of protecting the president and investigation into monetary related crime. The FBI came in early 20th century as a need to address more conventional crime that crossed state lines and made it difficult for states to investigate/prosecute (organized crime, kidnapping, bootlegging). While you could say it had a valid reason to exist, J. Edgar Hoover morphed it into something entirely different. Edit: To clarify my hastily typed up message from my phone, the Pinkertons were government contractors and precursor to the Secret Service, but not the same entity. Secret Service did not officially protect the president until the assassination of President McKinley in 1901.