Morris Cohen, an American who spied for the Soviet Union and was instrumental in relaying atomic bomb secrets to the Kremlin in the 1940s, has died without publicly revealing his source.
Cohen, best known in the West as Peter Kroger, died of heart failure in a Moscow hospital on June 23 at age 84. Russian newspapers reported his death Tuesday.
He took his most important secret with him: the name of the American scientist who helped pass vital information about the U.S. atomic bomb project at Los Alamos, N.M., in the mid-1940s.
“Thanks to Cohen, designers of the Soviet atomic bomb got piles of technical documentation straight from the secret laboratory in Los Alamos,” the newspaper Komsomolskaya Pravda said.
His methods will probably never be known, the newspaper said.
Cohen, the son of Russian immigrants, was born and raised in New York City. He joined the American Communist Party in 1935 and later went to Spain to fight with the leftwing Abraham Lincoln Brigade in the Spanish civil war.
While recovering from wounds, Cohen was recruited by Soviet intelligence to spy in America.
In July 1945, during the first test of the atomic bomb in Los Alamos, Cohen and his wife, Lona, recruited a Los Alamos scientist to obtain detailed blueprints of the weapon.
The information was passed to Moscow 12 days before the U.S. test.
Soviet dictator Josef Stalin ordered a crash program and exploded an atomic device four years later.
According to news reports in the 1990s, the information Cohen got from his still-unidentified source, code-named “Percy” by the FBI, was probably more important than data passed on by scientist Klaus Fuchs, who was arrested in Britain in 1950.
Cohen and his wife, tipped about their imminent arrest, fled to Moscow via Mexico. Four years later, they moved to New Zealand and changed their names to Peter and Helen Kroger.
Using the new names, they moved to London in 1954 and started a new intelligence network posing as rare book dealers. The network existed for seven years before British intelligence exposed it.
They were arrested in 1961 and sentenced to 20 years in prison. The couple was exchanged in 1969 for British teacher Gerald Brooke, arrested in Moscow for distributing anti-Communist propaganda.
Cohen’s wife died in 1992. Cohen was buried June 27 in a ceremony closed to the public so friends in the Russian intelligence community could attend.