Frederick Mayer (28 October 1921, Freiburg im Breisgau, Baden, Germany – 15 April 2016, Charles Town, Jefferson County, West Virginia)[1] was a German-born Jew who became an American spy as an OSS agent for the United States during World War II. He negotiated the surrender of the German Army in Innsbruck, Austria, in 1945 after he was captured serving in "Operation Greenup."