There's an obituary in the Times today on Ruth Greenglass, who passed away this past April. She was 84. (News of her death was only recently disclosed.)
The story of this Lower East Side native is fascinating.
As the Times notes, her husband, David, was an Army sergeant assigned as a machinist to the Manhattan Project, the program to develop the atomic bomb, at Los Alamos, N.M. Long story, but her testimony in the Rosenberg atomic-bomb spy case of the early 1950s helped lead to the execution of her sister-in-law Ethel Rosenberg. On June 19, 1953, Ethel and her husband Julius Rosenberg were put to death in the electric chair at Sing Sing. Greenglass' testimony was later called into question. She had lived the last four decades of her life under an assumed name.
It's all quite complicated. The FBI has the full story of the case here.