Who was the undercover cop in the film "Reservoir Dogs"?

The undercover cop in the 1992 film "Reservoir Dogs" is Mr. Orange. In a key scene near the end of the film, Mr. Orange explains to Marvin Nash (a kidnapped police officer) that he is an undercover cop and that the police will soon arrive to their location.

With the film "Reservoir Dogs", this is Quentin Tarantino's directorial debut. It is one film critics and fans have called unforgettable. The film was extremely popular and has been seen as raw, violent, and often mimicked. Within its story-line , there is a botched robbery that indicates a police informant. The pressure mounts in the aftermath of a diamond heist at a warehouse. Crime begets violence as the survivors unravel.