In '91, I read a book by David Lifton,
Best Evidence: Disguise and Deception in the Assassination of John F. Kennedy. It's now a permanent item in my library.
Lifton graduated from Cornell with a degree in physics, and was working on a degree in engineering at UCLA when the Zapruder Film was released. To him, the head snap sealed the deal that Kennedy was (also) shot from the front.
Interestingly, Lifton passed away just this month on St. Nicholas Feast Day (Dec. 6).
His friend at the time, a professor of law at UCLA, invited him to make his case to his law students. After a presentation of detailed and scientific evidence, and considering it with the entire body of evidence at their disposal, the law students all came down on the side of the Warren Report.
Lifton was flabbergasted. He wrote:
Arguing with the students and listening to them deliberate, I soon realized an investigation did not have to be an organized conspiracy to start with the Warren Commission's evidence and come to its conclusions. All that was needed were lawyers.
But his friend took him aside, and told him that his students were also considering the doctrine of
best evidence. What is more reliable, the evidence offered from a grad student's analysis of a 2D film, or the autopsy report, written by those who examined and handled the body of the President?
That launched him on the quest to trace the chain of custody of the body, and interview those who handled it. The Dallas doctors' descriptions differed dramatically from those in the autopsy report. The only logical conclusion, assuming each set of witnesses were truthful, is that the President's body was altered on Air Force One en route from Dallas to Bethesda.