"We made it our central program to see what might have changed since 1963. What had changed since 1963 are advances in science and technology," recalls G. Robert Blakey, the committee's chief counsel, who directed the investigation.
The committee reviewed all the evidence, and reaffirmed that Kennedy was shot and killed by Oswald.
With tension stemming from the Cold War, there was fear in the West that Soviet leaders in Moscow were directing a worldwide Communist conspiracy aimed at destroying the free world, including the United States.
The FBI knew that Oswald was a former U.S. Marine who had lived for almost three years in the Soviet Union, and returned to America with a Russian wife. They believed he was a committed Communist. Many Americans believed that Oswald's professed admiration for Cuba's Fidel Castro — who had established a Communist government allied with the Soviet Union just 100 miles from the United States — was proof somehow of a Communist conspiracy.
On Sept. 9, 1963, in a widely published interview with The Associated Press, Castro threatened American leaders. "We are prepared to fight and answer in kind," he said. "The United States leaders should think that if they are aiding terrorist plans to eliminate Cuban leaders, they themselves will not be safe."
Committee investigators went to Mexico City to check on allegations that Oswald had met with Cuban agents during a visit in 1963. And in 1978, they went to Havana to interview Castro himself.
"I sat in President Castro's office and, albeit diplomatically, looked at him in his eyes and said, 'Did you kill John Kennedy?,' " said Blakey, who headed the delegation. "And he said no. And then he told me why it would have been a foolish thing for him to have done."
According to Blakey, Castro said it would have been "insanity" for him to attack Kennedy. "That would have been the most perfect pretext for the United States to invade our country, which is what I have tried to prevent for all these years," Blakey says Castro told him.
"We looked as best we could for evidence that he might have done it," Blakey went on, "and we couldn't find it. That doesn't mean he didn't do it. It just means on the basis of the evidence that I have, I don't think that he did."
The committee combed Oswald's life for links to foreign governments. It heard testimony from a KGB officer who had handled Oswald's file when he was in Russia. The officer, Yuri Nosenko, says Oswald had tried to defect when he was in Russia, and the KGB would never have sent such an obvious target for suspicion back to the United States on an assassination mission. "KGB never will go on this because it's so obvious," Nosenko told ABCNEWS. Nosenko testified to the commission after himself defecting to the United States, where he still lives under an assumed name.
The special congressional committee spent two years on its investigation, and near the end was preparing a report saying that the Warren Commission was right: Oswald had been the sole assassin, and no one had conspired with him — not the CIA, the FBI, the Soviets or the Cubans. But a team of scientists surprised the committee with evidence that appeared to prove a conspiracy.