This document alleges that the CIA confirmed accused presidential assassin, Lee Harvey Oswald had worked for the CIA as a spy since 1957. It also says that CIA and FBI personnel were involved in President Kennedy's Assassination assassination, but the Agency itself was not responsible. The letter also mentions that the Director of the FBI, J. Edger Hoover was investigating Jimmy Hoffa's potential involvement with Lee Harvey Oswald.
The video below is AMAZING, despite the fact of the warning that it is age restricted so you can only watch it on YouTube.
This next excellent video from 1989 features former CIA officer, John Stockwell and really collaborates and supports a great deal on the CIA and FBI's involvement in the Assassination of President Kennedy.