I'm surprised they don't teach you about the Nixon tapes at Langley 
"The "Smoking Gun" tape revealed that Nixon instructed Haldeman to have the CIA pressure the FBI into dropping its Watergate investigation. Nixon instructed him to tell the CIA that the investigation would "open up the whole Bay of Pigs thing again". In his book, Haldeman later wrote: "It seems that in all those references to the Bay of Pigs, he was actually referring to the Kennedy assassination." He also said that Nixon might have been reminding CIA Director Richard Helms that the CIA assassination attempts on Fidel Castro may have triggered the assassination of Kennedy.
The unexplained 18+1⁄2 minute gap in Nixon's Oval Office recordings occurred during a discussion that included the President and Haldeman on June 20, 1972."
https://en.wikipedia.org/wiki/H._R._Haldeman
Nixon tried to use the stuff he knew about secret CIA operations to pressure Dick Helms to help him during the Watergate investigation.
If Nixon was suggesting to Helms that he knew (or believed?) Castro had killed JFK in retaliation for JFK's and the CIA's trying to kill him (Castro), he may have been right.
But you think the evil, evil, evil CIA killed him, don't you?