Another point that speaks against a proposed window shooter in that Crooks building is the fact that the FBI apparently gave the guy above his phone back with the above video still on it. Why give the phone back and/or not deleting that footage if there was such a shooter behind any of those windows? And if there was such a shooter, maybe they have analyzed the footage and came to the same conclusion as we, that you can't make out anything substantial there and that's why they gave it back? Or did they doctor the footage before they gave it back to the guy? Again, going by occam's razor, the simplest explanation is probably that the FBI knows that there was no second shooter behind any of those windows on Crooks building (and/or within somewhere else within that building) and therefore considered it safe to give that footage back. Also, the idea that a second shooter might have escaped quickly out of that building (or another building there) after the shots through that parking lot seems less likely because the guy above is also filming that area shortly after the shots. That doesn't mean though that the hypothesized second shooter didn't escape through that parking lot, because he could have escaped at a later point than it is shown in the footage.