or not ... the gun wasn't aimed at the wannabe assassin anymore. Those two guns the two Police counter-snipers had looked to be large caliber. If either of them did fire, wouldn't those bullets seriously mangle a human head if they hit? The photo circulating of a bloodied perp only show missing front teeth, no missing flesh.
I'm beginning to wonder if the reaction of disbelief shown by the Police sniper nearest the roof's edge, looking abruptly over his sight, was because a different counter-sniper had just eliminated the threat before he even fired. Maybe it was the guy next to him crouched at ridge level, or maybe a third counter-sniper not yet revealed.
The bullet entry point is the bridge of his nose. The back of his head would be missing. The bullet looks to have blown out his upper plate of teeth.
I suspect a 3rd LEO. See my posts above about the relative loudnesses and acoustic signatures of the shots in the various vids.