 It was through this appointment that he became an FBI Special Agent responsible for locating and arresting Nazi German spies in America.After working with the Federal Bureau of Investigation for about 10 years, Leon G. Turrou led the investigation into a Nazi spy ring operation in 1938.Although three Nazi spies were convicted and imprisoned and Turrou became famous, he deeply disappointed the FBI for leaking information about the case to the New York press and writing a series of articles about the case for a newspaper.