 A county sheriff from Nebraska whose wife and child died in a fire, O'Hara cut all ties with his past life.He put in an application with the United States Department of the Treasury, which accepted him.As a "T-Man," O'Hara was available to any of the various law enforcement agencies then part of the Department, all of which cooperated in this positive portrayal of their various organizations, much in the manner of the Los Angeles Police Department with Webb's "Dragnet" and "Adam-12."