Harry T. Thompson was a U.S. Navy yeoman who spied for Japan in the 1930's. Recruited by Japanese exchange student Toshio Miyazaki, Thompson sold engineering, gunnery, and tactical information about the Pacific Fleet in exchange for money. Arrested by the FBI in 1936, Thompson was tried and convicted under the Espionage Act of 1917 on July 2, 1936. He was sentenced to 15 years in prison.
(From: https://warfarehistorynetwork.com/daily/wwii/the-spies-of-pearl-harbor/)