Klaus Fuchs
Emil Julius Klaus Fuchs was a German theoretical physicist and atomic spy who, in 1950, was convicted of supplying information from the American, British, and Canadian Manhattan Project to the Soviet Union during and shortly after the Second World War. While at the Los Alamos National Laboratory, Fuchs was responsible for many significant theoretical calculations relating to the first nuclear weapons, and later, early models of the hydrogen bomb.
Emil Julius Klaus Fuchs was born in Rsselsheim, Grand Duchy of Hesse, onDecember 1911, the third of four children of a Lutheran pastor, Emil Fuchs, and his wife Else Wagner. Fuchs was always known by his last given name, Klaus. He had an older brother Gerhard, an older sister Elisabeth, and a younger sister, Kristel. The family moved to Eisenach, where he attended the gymnasium, and took his Abitur. At school, Fuchs and his siblings were taunted over his fathers unpopular political views, which they came to share. They became known as the red foxes, Fuchs being the German word for fox.
Source: Wikipedia