gave these ideas little credence. In later years, Donald Rickard, a former American diplomat, revealed that the Central Intelligence Agency, which feared Mandela's associations with communists, had informed the South African police of his location. Jailed in Johannesburg's Marshall Square prison, Mandela was charged with inciting workers' strikes and leaving the country without permission. Representing himself with Slovo as legal advisor, Mandela intended to use the trial to showcase "the ANC's moral opposition to racism" while supporters demonstrated outside the court. Moved to Pretoria, where Winnie could visit him, he began correspondence studies for a Bachelor of Laws (LLB) degree from the University of London International Programmes. His hearing began in October, but he disrupted proceedings by wearing a traditional kaross, refusing to call any witnesses, and turning his plea of mitigation into a political speech. Found guilty, he was sentenced to five years' imprisonment; as he left the courtroom, supporters sang "Nkosi Sikelel iAfrika". On 11 July 1963, police raided Liliesleaf Farm, arresting those that they found there and uncovering paperwork documenting MK's activities, some of which mentioned Mandela. The Rivonia Trial began at Pretoria Supreme Court in October, with Mandela and his comrades charged with four counts of sabotage and conspiracy to violently overthrow the government; their chief prosecutor was Percy Yutar. Judge Quartus de Wet soon threw out the prosecution's case for insufficient evidence, but Yutar reformulated the charges, presenting his new case from December 1963 until February 1964, calling 173 witnesses and bringing thousands of documents and photographs to the trial. Although four of the accused denied involvement with MK, Mandela and the other five accused admitted sabotage but denied that they had ever agreed to initiate guerrilla war against the government. They used the trial to highlight their political cause; at the opening of the defence's proceedings, Mandela gave his three-hour "I Am Prepared to Die" speech. That speech—which was inspired by Castro's "History Will Absolve Me"—was widely reported in the press despite official censorship. The trial gained international attention; there were global calls for the release of the accused from the United Nations and World Peace Council, while the University of London Union voted Mandela to its presidency. On 12 June 1964, justice De Wet found Mandela and two of his co-accused guilty on all four charges; although the prosecution had called for the death sentence to be applied, the judge instead condemned them