Spy. Police photograph of Physicist Klaus Fuchs. In 1933 Fuchs fled Germany for Britain. During the War he worked on the Manhattan Project in the United States to build the Atomic Bomb and later worked on British nuclear projects. In 1950 he admitted spying for the Russians since 1942 and passing on details of British and American nuclear technology.
Klaus Emil Julius Fuchs (29 December 1911 – 28 January 1988) was a German theoretical physicist and atomic spy who in 1950 was convicted of supplying information from the American, British and Canadian atomic bomb research (the Manhattan Project) to the USSR during and shortly after World War II. http://en.wikipedia.org/wiki/Klaus_Fuchs