NEW YORK — David Greenglass, who served 10 years in prison for his role in the most explosive atomic spying case of the Cold War and gave testimony that sent his brother-in-law and his sister, Julius and Ethel Rosenberg, to the electric chair in 1953, has died at 92. Greenglass — who admitted decades later that he lied on the stand about his own sister — died in New York City on July 1, according to the Rosenbergs' sons, Michael and Robert Meeropol.
After his release from prison in 1960, Greenglass lived under an assumed name in Queens, hoping to be forgotten for his part in a McCarthy-era cause celebre that is still furiously debated to this day.
A spokeswoman for the Meeropols, Amber Black, said the brothers were aware of their uncle's death last summer but did not seek media attention and received no inquiries at the time.
The Rosenbergs were convicted in 1951 of conspiring to steal atomic secrets for the Soviet Union and were executed at New York's Sing Sing prison, insisting to the very end that they were innocent.
Greenglass, indicted as a co-conspirator, testified for the government that he had given the Rosenbergs research data obtained through his wartime job as an Army machinist at Los Alamos, New Mexico, headquarters of the top-secret Manhattan Project to build the atomic bomb.
He told of seeing his older sister transcribing the information on a portable typewriter at the Rosenbergs' New York apartment in 1945. That testimony proved crucial in convicting Ethel along with her husband.
In 2001, in revelations more boastful than contrite, Greenglass was quoted in a book, "The Brother," as saying he had not actually seen Ethel typing and knew of it only from his wife, Ruth. For the prosecution, however, the typewriter "was as good as a smoking gun in Ethel Rosenberg's hands," author Sam Roberts wrote.
In the book and a CBS television interview, Greenglass shrugged off any idea of a betrayal. He said he lied to assure leniency for himself and keep his wife out of prison so she could care for their two children.
"As a spy who turned his family in ... I don't care. I sleep well," Greenglass said in the interview, adding that "stupidity" had kept the Rosenbergs from possibly saving themselves by admitting guilt.
Greenglass said that while history might blame him for the Rosenbergs' deaths, he hadn't known that would be their fate — and that in any case, his own family came first. He also said he had been urged to lie by prosecutors, among them Roy Cohn, later a key aide to anti-communism crusader Sen. Joseph McCarthy.
To some, he came to be regarded as a symbol of betrayal. In the 1989 Woody Allen movie "Crimes and Misdemeanors," Allen's character says of his smug and annoying brother-in-law: "I love him like a brother — David Greenglass."
Greenglass was born in New York in 1922. After Army service in World War II, including the Los Alamos assignment, he and Julius Rosenberg became partners in a machine shop. The business failed; a Rosenberg attorney later claimed that led Greenglass to seek revenge on his brother-in-law.
In fact, David and Ruth Greenglass, like the Rosenbergs, were active communist sympathizers, having joined the Young Communist League in 1943. Both couples believed that the Soviet Union should have the bomb if the United States did.
At trial, the Greenglasses said Julius Rosenberg had recruited David Greenglass as a spy and arranged for him to feed stolen atomic research and a detonator to a go-between, Harry Gold. Gold also was later convicted.
Greenglass served 10 years of a 15-year sentence for espionage. After his release, he lived with his family in quiet anonymity as controversy over the Rosenberg case rose and ebbed over 40 years.
Greenglass remained estranged for the rest of his life from the Rosenbergs' sons, who were 10 and 6 when their parents were executed. The brother later took their adoptive parents' surname, Meeropol.
Author Roberts wrote that while Greenglass was willing to see his nephews, he remarked that "their whole life has been involved with this kind of stupidity, to actually think they (the Rosenbergs) were innocent."