State Counter-Snipers had the roof covered from a window adjacent to the shooter. (An easy shot to Crooks’ position).
It appears the rifle was momentarily abandoned to answer a legitimate call to go downstairs and open a pass-key door.
(The “Swiss-Cheese” Theory at work—not that I’m convinced).
There would have been no Swiss cheese possible if the SS had accepted the offer of the local police drone.
This was a blatant inside job.