At minimum the evidence is strong for a CIA JFK coverup -- see last video, for example. It doesn't mean they did it, ofc. Johnson pressured Warren to lead the commission with the argument that if the public became convinced the Soviets/Cubans were behind it WW3 would result. This could have affected CIA actions post-Dallas as well. But I suspect something more sinister on the part of certain elements of CIA, and there is tons of evidence to that effect leaking out over the years.
I enjoy listening to Mark Lane speak even if he turns out to be incorrect in some or many of his allegations. I think he destroys Buckley in their debate: Lane the Rationalist and Buckley a good example of motivated or biased reasoning.
I've followed Spygate for 4 years now, with the media covering it up and FBI/CIA refusing to produce documents, Barr probably acting to protect the institutions, FISA court obviously corrupt, etc. The JFK matter has a very familiar feel to it. [ Should add the Epstein matter, which unfolded in plain sight over 20y, as another example. ]
Mark Lane, at the peak of his powers, discusses the Warren Commission report with William F. Buckley (1966):
Mark Lane, near the end of his life:
Astonishing 2014 claims about the Zapruder film in CIA hands in the days after Dallas: the creation of two different briefing boards, one seen by CIA director John McCone, the other given to the Warren Commission. The interview is remarkable.
Horne and Brugioni strike me as very credible. CIA NPIC's main activity was interpreting U2 spy plane photographs, and had some of the most advanced photographic technology of the era. They were a logical choice to have a first look at the Zapruder film, but Brugioni did not learn until decades later that the CIA modified the film (removing certain frames, esp. near #313 which shows Kennedy's head exploding) and only gave a full briefing to McCone while witholding information from the Warren Commission.
While serving as chief analyst of military records at the Assassination Records Review Board in 1997, Douglas Horne discovered that the Zapruder Film was examined by the CIA's National Photographic Interpretation Center two days after the assassination of President Kennedy.
In this film, Horne interviews legendary NPIC photo interpreter Dino Brugioni, who speaks for the first time about another NPIC examination of the film the day after the assassination. Brugioni didn't know about the second examination and believes the Zapruder Film in the archives today is not the film he saw the day after the assassination.
Bonus: Interview with son of E. Howard Hunt (CIA, convicted Watergate Plumber), including audio of Hunt's confession. Note link to Cord Meyer, also see Mary Meyer 1964 execution in Georgetown...
Rolling Stone article (2007).
James Jesus Angleton -- "A Wilderness of Mirrors"
Note Added in response to a question in the comments:
I suggest you invest an hour or two in
1. Brugioni interview: establishes that a conspiracy at the highest level of CIA to alter the film evidence was in place within ~24h of the shooting. Hard to explain unless there was very strong motivation already... bureaucracies usually can't react that fast when *surprised* by events.
2. Interview with Hunt's son, concerning his deathbed confession of being aware of (and playing a minor role in) the assassination conspiracy. Hunt is a well-known CIA figure who was involved in lots of covert ops including Watergate. You don't have to accept this as fully credible of course, but you can't say that conspiracy didn't happen because otherwise information would have leaked out. It may very well have leaked out! But few pay attention because of the groupthink against "conspiracy theory" (this term was literally invented and promulgated by CIA to discourage public attention to what it was doing during the Cold War).
I would say I am very confident of an active cover up post assasination, less confident of a CIA role in the killing.
Other facts that have leaked out (now confirmed by official documents and the official CIA historian) include the fact that CIA was very closely monitoring Oswald starting in 1959 and that his file was closely held by none other than CIA prince of darkness James Jesus Angleton. Now look into the unsolved killing of Angleton's friend Mary Meyer (who was having an affair with JFK when he was shot) in 1964 and you are off to the races... Their common friend Ben Bradlee (WaPo editor of Watergate fame) wrote in his memoirs of catching Angleton, having broken into Meyer's house, with her diary...
BTW, over the years it was wrongly reported that RFK did NOT believe in a conspiracy against his brother. The evidence is pretty convincing now that he always believed in a conspiracy but didn't admit it in public.