When the presidential limousine emerges into view from the sign on the lower left, Kennedy has already been shot once. You can see his hands go to his throat where there was an exit wound from what has been called the magic bullet. (The movement of the hands-which look unusual- is most likely a medical phenomenon called "Thorburn's Positon" which is an involuntary movement of the hands and arms in a vertical manner in response to a spinal injury, first noted by a neurologist in the early 19th century I believe.) If you also look carefully in the lower left, you can see the umbrella open by Umbrella man.
Long a conspiracy theory mystery, Umbrella man- the man who opened a black umbrella on a warm sunny Dallas day at the moment the president was shot, turned out to be a normal citizen who was, of all things, protesting the appeasement policy of President Kennedy's father - Joseph P. Kennedy, when he was ambassador to the court of Saint James. The umbrella was to symbolize the Ambassador's support for Prime Minister Neville Chamberlin's appeasement policy. Chamberlin often carried an umbrella. For more on the unusual circumstances of Delay Plaza that day, see John Updike's comment in a 1967 New Yorker article:
We wonder whether a genuine mystery is being concealed here or whether any similar scrutiny of a minute section of time and space would yield similar strangenesses—gaps, inconsistencies, warps, and bubbles in the surface of circumstance. Perhaps, as with the elements of matter, investigation passes a threshold of common sense and enters a sub-atomic realm where laws are mocked, where persons have the life-span of beta particles and the transparency of neutrinos, and where a rough kind of averaging out must substitute for absolute truth. The truth about those seconds in Dallas is especially elusive; the search for it seems to demonstrate how perilously empiricism verges on magic.
We've thought about this long and hard. We've read at least a dozen books (we highly recommend the re-release of William Manchester's "Death of a President") and we've personally inspected Dealey Plaza on two occasions, once as an unofficial advisor to a documentary being made.
Oswald killed Kennedy by himself. It hurts that such a small, insignificant failure of a man killed such a great man. But he did. By himself. With a cheap Italian WWII surplus rifle.
Our favourite book on the assassination is a work of fiction: Stephen King's 11/22/1963. Read it. You'll be glad you did.
Frame 313 of the Zapruder film is the head/kill shot. 50 years later it still remains perhaps the most disturbing film image of our time. A young man, slain down at the prime of his life.