On June 19th, 1953, Julius and Ethel Rosenberg were electrocuted for providing the Soviets with information on the atomic bomb.
According to charges against the Rosenbergs, the couple had been providing the Soviets with vital information from June of 1944. Repeated appeals for clemency were denied.
Julius Rosenberg became an engineer working for the Army Signal Corps Engineering Laboratories at Fort Monmouth, New Jersey. It is believed that he was recruited in 1942 by the Soviet Union to spy on their behalf. Rosenberg was able to send the Russians thousands of documents on the nuclear program, including information on the fuse for the bomb. Rosenberg also managed to recruit a number of others who were working on the bomb to spy on behalf of the Soviets.
Rosenberg was discovered as a result of an unraveling of a Soviet spy ring. The US caught Klaus Fuchs who had worked at the British Consulate and had been giving information to the Soviets. He gave up Harry Gold as a courier and Gold, in turn, incriminated David Greenglass who was Rosenberg's brother. Greenglass then accused Rosenberg. Rosenberg was arrested on June 17, 1950. His wife Ethel was arrested on August 11th after testifying to the Grand Jury. Both were charged with espionage. The charges against Ethel were thin based on the second testimony of Greenglass that she had taken notes when they met. The Government demanded the death penalty.
The Rosenbergs trial began on March 6, 1951. Judge Irving Kaufman presided. On March 29th they were convicted, and Kaufman sentenced both of them to death on April 5th, 1951. Despite a concerted public effort on behalf of the Rosenbergs the government pushed to go ahead with the execution. That decision was especially problematic when it came to Ethel whom evidence indicates was not guilty ( and the author of this has first-hand information to this fact). The two were executed on June 19th, 1953.