HSienzant
Philosopher
This is quite salient because we already have the problem of the transverse shot. From the TSBD, Kennedy's car was traveling away, along the line of sight, and down an incline. In contrast, from the fence at the top of the grassy knoll the target is moving rapidly across the line of sight. That's already a difficult shot. The road signs and trees limit the time in which the shot can be taken. When you add the obstructions caused by using the fence as cover, making the fatal head shot from there, with a suppressed weapon, strains credulity.
And when you add in the fact that twelve men were on the overpass directly over Elm Street about fifty feet from this supposed shooter, it strains credulity to the breaking point. He would have had to crawl into this sewer opening in full view of numerous railroad workers, at least one police officer stationed on the overpass, two parking lot attendants, and Lee Bowers.
http://i74.servimg.com/u/f74/18/50/79/06/thomps21.jpg