John Semer Farnsworth (August 13, 1893 - November 10, 1952) was a former United States Navy officer who was convicted of spying for Japan during the 1930s. He was identified as Agent K in radio messages intercepted by the Office of Naval Intelligence.
Read more about John Semer Farnsworth: Naval Career and Court-martial, A Career in Spying, Meetings With A Journalist, Arrest, Trial and Conviction, Sentencing and Appeal