Zapruder was not standing on the grassy knoll, but on the concrete wing jutting out into Dealey Plaza right adjacent to the grassy knoll. His secretary was right behind Zapruder kolding onto his jacket to give him some support as Zapruder had vertigo. If anyone shot a rifle from the picket fence behind the grassy knoll, it would have been to Zapruder’s immediate right at about 20 feet away. The top of the fence would (And still is) at the level of your feet if you stand there. Have you stood there? I have many times. You would be looking right down at the shooter. The Zapruder film pans across the top of the knoll and ends with a short glimpse of the fence and what was behind it. Nothing. You can’t convince me that Zapruder, with his Army training, would not be able to see and especially hear a shot if one had been taken from behind the fence. It did not happen.Nix captures Zapruder on his film.
Zapruder’s film did not capture the fence area during the assassination itself since his filming was focused on Kennedy and not the grassy knoll or fence area. The fact he shows the fence after Kennedy’s car was going through the underpass is pretty much irrelevant since any shooter would have been long gone.
None of the films including the Zapruder film prove or disprove a shooter standing behind the fence. There is little evidence one way or the other. We may never know the details of what went down.
We lived in Texas during that time and went through it months after the assassination.