Private Mitchell was a member of the US Military Police stationed at Hangar 51 in 1957. He served under Sergeant Jimmy Wycroft.
Biography
Unlike Corporal Higgins, Mitchell was new, and thought they should report the unexpected visit of a mysterious American army officer, "Colonel Truman" and his men during the time when he and the other MPs were left on gate duty. Mitchell's fears proved well-founded: the "Americans" were actually disguised Soviet troops. Sergeant Wycroft, after being shot, hoped that Mitchell escaped, but realized that he too had been killed together with the other MPs by the Soviets shortly before expiring himself.
Behind the scenes
In Indiana Jones and the Kingdom of the Crystal Skull, no names are given for the policemen on guard. Mitchell's name is only indicated in the film's novelization. It therefore remains unclear whether he is the M.P. in Guard Hut appearing in the film's credits who was played by Kevin Collins.
In LEGO Indiana Jones 2: The Adventure Continues, the MPs survive their encounter with the Soviets and are taken hostage. They are later forced to flee Hangar 51.