Ruth Greenglass, whose testimony in a sensational Cold War espionage trial helped send her sister-in-law Ethel Rosenberg to the electric chair, has died.
She was 84, and had been living under an alias to avoid association with the case that led to the execution of Julius and Ethel Rosenberg in 1953.
Her death was revealed in court documents filed by prosecutors in late June. The papers did not say when she died.
Greenglass and her husband, David, were pivotal figures in the spy case. They confessed to being part of an effort to smuggle secrets to the Soviets, and turned in the Rosenbergs, their own relatives, as the spies who recruited them to the task.
Historians continue to debate the truthfulness of their testimony concerning Ethel, whose guilt has long been questioned.
During the 1951 trial, the couple said they saw Ethel transcribing stolen atomic secrets on a portable typewriter in her New York apartment.
Their account was the best piece of evidence linking Ethel, David's sister, to an alleged plot to steal research data from the Manhattan Project.
It was also self-serving. By cooperating, David Greenglass, a wartime machinist in Los Alamos, New Mexico, who had been charged along with the Rosenbergs, was spared a possible death sentence.