FBI/CIA/Organized crime, all of them had a hand. The cover-up went all the way to the White House. LBJ had what he called his “trigger man” Malcolm Wallace who had killed LBJ’s sisters lover, and received a 5 year suspended sentence for it. LBJ was neck deep into organized crime, the FBI and the CIA both hated Kennedy. All of the above had the means, motive and opportunity to assassinate the President. Are you one of the few who actually believes the LHO lone nut story concocted by the Deep state?
But that doesnt necessarily mean the FBI was involved in any aspect of the conspiracy. And it is not impossible the killers were tied to the KGB and/or Castro.