David Greenglass, whose name for many became synonymous with betrayal after he gave testimony that sent his sister and brother-in-law, Ethel and Julius Rosenberg, to the electric chair in 1953, has died at age 92. Greenglass died in New City on July 1, according to family members. Greenglass served almost 10 years in prison for his role in the Cold War's most explosive spy case, in which the Rosenbergs were convicted of passing atomic secrets to the Soviet Union. After his release from jail he changed his name and lived quietly until a journalist tracked him down decades later. At that time, he admitted that he had lied on the stand to save his wife from prosecution and gain leniency for himself, giving testimony he was not sure of but that helped lead to his brother-in-law and sister's executions.