With cameras everywhere there has to be a video of it if true.
This is a very reasonable analysis .
I was of the opinion that there was only one shooter and the rest of the shots were from counter snipers.
This makes sense and we shall have to wait and see.
The number of empty brass shells found on the roof would be helpful but if there was coordination the shooter on the roof may have brought a few extras as a distraction.
If there was fire coming from the building they will find powder residue from the second shooting location.
With all the video and audio available they should be able to very precisely determine the location of the various shooting locations.