So what did the witnesses tell lawmakers? Testimony from Stone and authors Jefferson Morley and James DiEugenio largely centered around criticism of the CIA and other federal officials in the decades since Kennedy's assassination.

American filmmaker Oliver Stone said Tuesday that the assassination of former President John F. Kennedy is “a cold case with a lot of clues” after he testified before Congress earlier in the day.

Oliver Stone's "JFK" was nominated for eight Oscars and grossed more than $200 million but was also dogged by questions about its historical accuracy.