A friend of mine, who dies recently, was a young Navy Seal assigned to the CIA as part of the Bay of Pigs invasion fiasco. He was waiting off shore of Cuba when the invasion was aborted by Kennedy and went back to Miami and then Washington, DC.
My friend says that the CIA killed Kennedy in a multi-actor assassination using an umbrella gun to shoot a flechette into Kennedy’s throat as the first shot from 15 feet away. The flechette was made of hard, dissolvable gelatin and contained a paralyzing agent. This caused Kennedy to grab his throat, but it made his body rigid, which allowed Oswald to have an easier target and would make it harder for the SS to push Kennedy to the floor of the limo.
Here is a link of the event that my friend said was pretty accurate:
https://ratical.org/ratville/JFK/TUM.html
For what it is worth....
Kennedy wore a back brace for years as a result of a back injury he suffered in college. The injury was further exacerbated on the night of Aug. 1, 1943 when his PT boat, the 109 was rammed by the Japanese destroyer “Amagiri’’ and Kennedy was slammed against the wheelhouse. Kennedy also suffered from Addison’s disease.