Nazi Agent is a 1942 American spy film directed by Jules Dassin. It stars Conrad Veidt playing identical twins, one loyal to the United States U.S., the other a dedicated German Nazi.
Becker becomes acquainted with Kaaren De Relle Anne Ayars. She had been a secret agent loyal to the Nazis, but has become disillusioned by what she has seen and now continues with her duties for the spy ring only to prevent the Nazis from taking retribution against her family still in occupied France. She had spurned von Detners romantic advances in the past. However, she finds the baron changed, and for the better, when Becker shows sympathy for her plight.Information provided by Becker foils a plot to blow up a freighter loaded with explosive chemicals in the Panama Canal. He also learns the names of German agents working in America he mails the list, omitting De Relles name, to the FBI. Amid the betrayal and failure of their plans, some members of the spy ring turn against and kill each other others are arrested. ........
Source: Wikipedia