The Nazi Spy is a nameless Nazi spy and the main antagonist of the 1942 Abbott and Costello comedy/mystery film "Who Done It?. He is also a serial killer.
He was portrayed by Don Porter.
Chick Larkin (Abbott) and Mervyn Milgrim (Costello) both work at the soda counter of a local radio station. Their true passion, however, is to become writers on a radio mystery show. They attend a broadcast of the radio program Murder at Midnight along with one of the writers, Jimmy Turner and the producer, Jane Little.
As the show begins, the network president, Colonel J.R. Andrews, is mysteriously electrocuted to death. Seeing this as an opportunity to become radio writers, Chick and Mervyn impersonate detectives and attempt to solve the crime.
Larkin and Milgrim later flee the studio because they're accused of being the culprits. But afterwards, they hear that Milgrim has apparently won $10,000 on the Wheel of Fortune radio program, for which he must return to the studio in order to claim the prize. Larkin and Milgrim return and claim the prize (along with their own radio), only to later be arrested by the real detectives, whom Turner and Little manage to convince that there, should be a full re-enactment of the program that led to the murders, under the ruse that the true culprit will be revealed.
The Nazi spy, who uses the radio station to transmit information to his cohorts, attends the broadcast. It turns out that the spy murdered the Colonel and his physician because they found out about his illegal radio transmissions. During the broadcast, he is revealed to be the killer and escapes to the roof, where he is nabbed by Larkin and Milgrim and later arrested by the authorities.