MOSCOW -- Exiled American spy Morris Cohen has died in Moscow without ever unmasking a prominent U.S. scientist he says leaked atomic bomb blueprints to the Soviets in 1945.
Mr. Cohen's death was announced yesterday by one of the successor agencies of the KGB, which guarded and pampered the native New Yorker for the past 25 years. He lived six blocks from the U.S. Embassy.
Mr. Cohen, who died Friday at 84, is credited by Russian intelligence with founding a never-uncovered spy ring that stole atomic secrets from Los Alamos with the help of his lifelong spy partner and wife, Lona Petka Cohen. She died here in 1992.
The Los Alamos ring's most spectacular accomplishment came on July 4, 1945, when the New York headquarters of the NKVD, Josef Stalin's infamous secret police agency, cabled Moscow that the United States was about to test the world's first atomic weapon.
Russian documents show that by the time the test bomb detonated in the New Mexico desert 12 days later, Soviet scientists had a precise description of it.
Under a crash program ordered by Stalin, the Soviets stunned the world by setting off an exact duplicate of the American bomb in 1949, spawning a nuclear spiral that cost trillions of dollars before the arms race helped bankrupt the Soviet Union in the late 1980s.
Within months, American code-breakers identified and sent to prison one of the Soviet sources at Los Alamos, British physicist Klaus Fuchs. But it remained secret for almost 50 years that the Soviets also may have recruited another Los Alamos scientist who was an American.
In Russian interviews a few months before his death, Mr. Cohen said that he and his wife had secret dealings with a young American scientist in the Manhattan Project but he refused to identify him.
The Cohens' role in atomic espionage only surfaced in 1991. In a partly fictionalized account, a KGB colonel wrote that the Cohens had ferreted atomic secrets from Los Alamos with the help of an "American physicist" called "Perseus." The FBI is investigating claims of the existence of "Perseus."
Mr. Cohen, infused with idealistic thoughts during the Depression, joined the American Communist Party in 1935 and then enlisted to fight with the leftist Abraham Lincoln Brigade in the Spanish Civil War.
Hit in both legs by machine gun fire during his first battle, Mr. Cohenspent four months in a hospital ward. While recuperating in the spring of 1938, he was one of a handful of American volunteers chosen by Soviet intelligence officers to return to America and become Soviet spies.
After allegedly assembling a spy network that included "Perseus," Mr. Cohen was drafted into the U.S. Army in July 1942, leaving his bride Lona to carry out risky courier assignments.
In the summer of 1950, the Cohens were tipped off by a Soviet diplomat about a coming FBI crackdown and fled to Moscow through Mexico. Four years later, after undergoing spy training here and in Poland, they surfaced in England under the names Peter and Helen Kroger of New Zealand.
For six years Mr. Cohen led a double life as a London rare book dealer and secret radio operator for the Soviets. In 1961, he and his wife were trapped by British agents and convicted of conspiring to steal British submarine warfare secrets. They spent nine years in jail before the KGB managed to extract them in a spy swap for an imprisoned Briton.
The Cohens, who had no children, spent part of the last two decades training young Russians to be Soviet spies in the West.
His funeral yesterday was closed to outsiders so that his former colleagues could attend without fear of being identified, said a spokesman for the Russian intelligence service.