It was one of the most notorious spy cases in US history. On 27th November 1954, former US diplomat Alger Hiss was released after spending four years in jail for allegedly lying about being a Soviet agent. Alger Hiss had been seen as a potential secretary of state, but was unable to shake off allegations that he'd passed official documents to Moscow. His conviction was the prelude to a Communist witch-hunt in America that became known as the McCarthy era. Louise Hidalgo has been talking to Alger Hiss's son Tony Hiss about growing up in the shadow of the scandal, and his belief that his father was innocent. Picture: US state department official, Alger Hiss, denying he was a member of a Communist cell before the House Committee on Un-American Activities in Washington on 28th August 1948. (Credit: William Bond/Keystone/Getty Images)