David Greenglass

David Greenglass, who was assigned as a machinist to the Manhattan Project to build the atomic bomb, provided the Rosenbergs with data on nuclear weapons. The Rosenbergs turned over this information to Harry Gold, a Swiss-born courier for the espionage ring, who then passed it…

…examination of Ethel Rosenberg’s brother, David Greenglass, was crucial in securing the couple’s convictions. Greenglass later said he had lied under oath at Cohn’s inducement.