Counter Espionage

CounterEspionage is a 1942 American comedy film directed by Edward Dmytryk. CounterEspionage was the ninth film in Columbias Lone Wolf series, based on characters created by Louis Joseph Vance. It is also known as The Lone Wolf in Scotland Yard.

Kent Wells happened to see Harvey go through his briefcase, and when he goes upstairs to the mansions top floor, he sees someone opening Sir Staffords safe in the library. Before Wells has any chance of stopping him, the man is off with the plan for the governments new secret weapon the beam detector. The man drops a cufflink wih the letter L on it.Sir Stafford involves the Scotland Yard in the investigation of the stolen plans. Two American Inspectors, Crane and Dickens, are visiting the Yard and are invited by the chief investigator on the case, Inspector J. Stephens of the Scotland Yard. The three men go to the Hart mansion, and conclude that the L must mean that notorious jewel thief Michael Lanyard is responsible for the theft. He is also known as the Lone Wolf. ........

Source: Wikipedia