Klaus Fuchs, a German-born physicist who passed American and British secrets of the atom bomb to the Soviet Union in the 1940s, died today in East Germany, the state-run ADN news agency said. He was 76.
A brilliant contributor to Britain's wartime and postwar atom-bomb research, Fuchs regularly passed the fruits of his own and his colleagues' work to the Soviet Union.
ADN did not give a cause of death.
Upon his detection and subsequent confession, he was described as the living embodiment of Dr. Jekyll and Mr. Hyde.
He served about 9 1/2 years of a 14-year jail sentence and was released in June, 1959, when he moved to East Germany.
Authorities have said his espionage cut at least one year off the time it would have taken the Soviets to develop their own atomic weapon.
At his preliminary hearing, the British prosecutor had this to say:
"He produced in himself a classic example of that immortal duality of English literature--a Jekyll and Hyde. As Jekyll he was a normal citizen in the use of his magnificent brain in the cause of science; as Hyde, he was betraying . . . his oath of allegiance, his vows of security and the friendship of his friends."
Fuchs, born near Frankfurt in 1911 of a German Quaker family, was educated in the tradition of his scientist father, a professor at the universities of Leipzig and Kiel, and in 1933 fled to England from Nazi Germany.
He was interned in Canada as an alien in 1940, but later became a British citizen and made no attempt to hide his communist sympathies.
First recruited for service in Britain's secret atomic research program, he began work on the development of the atomic bomb in the United States in 1943, a year after he began passing secrets.
He was at the American atomic establishment at Los Alamos, N.M., from 1944 to 1946.
Fuchs was arrested in 1950 after a lengthy FBI investigation, pleaded guilty to being a communist spy and was imprisoned.
In his confession, he said his belief in Marxism enabled him to live the double life of researcher and spy.
"Looking back on it now, the best way is to call it controlled schizophrenia," Fuchs said.
Forced Change in Policy
Fuchs's exposure as a spy forced Britain to change its naturalization policy so that for years, known communists and fascists were not granted citizenship.
In East Germany, he eventually became director of the nation's Institute for Nuclear Physics. He was also a member of the East German Communist Party's central committee and a senior member of the country's Academy of Sciences.
In 1959, Fuchs married Greta Keilson, a long-time Communist. It could not be immediately determined if she is alive and ADN did not mention survivors.
Two books were published last year on Fuchs--one by American historian Robert Chadwell Williams, the other by British journalist Norman Moss.