Circled in the middle -- is JFK's limo 30ft from the approaching underpass.
So at an estimate, in the 3 to 6 seconds after the head shot.
Railway workers stood nearby said:
S. M. Holland -- ''I made it very clear to the Warren people one of the shots came from behind that picket fence. I heard the report and saw
the smoke come out about 6 or 8 feet above the ground, right out from under those trees. There is no doubt whatsoever in my mind . . .''
Richard Dodd -- ''all four of us, all railroad men, standing here, seen about the same thing. The smoke came from behind the hedge -- and a motorcycle policeman dropped his cycle in the street and run up the embankment''
There's a very good old thread about this on the ed forum
google -- "Witnesses who say a shot and smoke came from behind the picket fence"
Interesting Youtube clip re 'do rifles produce smoke when fired' from footage of Charles Whitman 'Texas Tower Sniper'
I asked if the Wiegman still has been debunked because some have said it's just branches from the nearby tree ... which it obviously could be. But it fits with Holland's description ''the smoke come out about 6 or 8 feet above the ground''. The Wiegman film is so brief and all over the place it's hard to conclude much.
If people smelt gun powder, plus we have a photo of what appears like a smokey cloud hovering around the picket fence as described -- nothing changes. Because the eye witnesses who saw smoke weren't taken seriously by the investigators at the time.