I have been reading David Lifton's book Best Evidence with great interest. The book details Lifton's 15 year preoccupation with the evidence of the Zapruder film and President Kennedy's body. He basically proved with this that there were other assassins in front of Kennedy and that the plotters altered Kennedy's body to make it look like he was struck only from behind where Oswald worked in the Book Depository. The part where he confronted former CIA chief Allen Dulles at a public lecture at UCLA struck a chord with me. At this meeting Lifton presented to Dulles the frames of the Zapruder film which show Kennedy's head snapping backward when he received the fatal wound.
Everybody can see this in the Zapruder film, but not Allen Dulles. After much evasion Dulles was finally forced to look at the films and got very angry and said, "You have nothing! Absouluetly NOTHING! The head could be going around in circles for all I can see. You can't see a thing here! I have examined the film in the Archives many times. THIS proves nothing!"
After Dulles got to see the pictures Lifton passed them around to the 40 or so students present and meanwhile Dulles waved his hands saying, "I can't see a blasted thing here. You can't say the head goes back....I can't see it going back...it does not go back...you can't say that...you haven't shown it...."
When people are presented with direct evidence of something and they refuse to even try to account for it and rather simply deny it, it is clear they are lying. I had this experience with former CIA Officer Ed Kane interviewing him for my master's thesis "U.S. Covert Intervention in Iraq, 1958-1963."
Kane vehemently denied that the CIA had anything to do with it. In a letter to the Public Relations Director of the CIA, he stated “that the coup of February 8th, 1963 was a complete surprise to the agency and, I am certain, to the entire US government.” In 2005, I presented the document “Komer to Kennedy” to Kane via FAX. When I asked him, “who is the "they" Komer is referring to?” He replied,
"I have ABSOLUTELY no idea. I saw NO reporting, from any source, including overhead and communications intercepts, while I was Iraqi desk officer even HINTING at a coup in the making. Neither did anybody in State. When I phoned my Agency superiors from HQS about midnight on February 8th, they all expressed astonishment that a coup had taken place."
On the phone, I asked him for clarification. What then was Komer talking about? “I think he was talking through his hat,” Kane replied. Kane would have us believe that he is telling the truth, but Bob Komer was lying to the President of the United States in a Top Secret memo. Kane and Dulles were actively promoting what the agency calls “white propaganda:” lies are told to the public to make your side look good. This is a part of what they euphemistically title “tradecraft.”
If you are interested in reading more about this I can email you the microsoft Word copy of my paper and you can read Appendix 1, The Secrecy of U.S. Covert Intervention. Appendix 3 contains copies of all the documents I keep referencing.
 David Lifton, Best Evidence, Disguise and Deception in the Assassination of John F. Kennedy, New York, 1980, page 41.
 Interview with Retired CIA Case Officer, Ed Kane, June 2005.
 Letter from Ed Kane to CIA Director of Public Relations in William Zeman, "U.S. Covert Intervention in Iraq, 1958-1963," page 98.
 Correspondence with Retired CIA Case Officer, Ed Kane, June 2006.
 Interview with Kane, June 2005.