The surprise ambush from above and behind was a very effective one then. Don’t you agree? However, there was at least one person who had it figured out. Here’s an image from Elsie Dorman’s film of what I believe is Howard Brennan’s squatting in the shadows of the wall he had been sitting on and looking up towards the sniper’s nest. This is just before LHO fired the third shot.


Judging the position of other people standing around that water pool, makes me think that the Dorman still frame is After the 3rd shot. That railroad guy in Overalls appears to be looking toward the Triple Underpass. The other people seem to be meandering around like the bulk of the motorcade had passed by. I need to see a clearer still frame to judge the posture of Brennan.
With respect to the position of shooters, though it got a lot of stuff wrong, I believe "The Men Who Killed Kennedy" (1988) got this one right. 3 total shooters. 1 in Front, 2 Behind. 1 of the behind shooters being, "almost on the horizontal". "Almost on the horizontal" would include the Bushes/Shrubs/ Garden that run down the Elm St Ext. If you look at the uncropped Bothun Photo that shows the Umbrella Man & DCM sitting on the Elm St curb, in the background there is a Black Figure moving down the sidewalk that leads from the (E) pergola Shelter down to Elm St. This photo is roughly :45+ after the kill shot. You know how close that (E) pergola shelter and the sidewalk is to the Bushes/Shrubs/Garden. DPD Officer Smith running up the Elm St Ext roughly:20 seconds after the kill shot, could have flushed this Black Figure out of the Bushes/Shrubs/Garden area into the (E) shelter/sidewalk. This (E) shelter/sidewalk area is Not where anyone would choose to watch the motorcade from. (The Bothun Photo is posted in this forum's "Photo Gallery")