The only thing I know for sure is that we will never know for sure:
Because no matter what we learn, and no matter what we can assume from logic and analysis, those who made it happen or merely allowed it to happen will never admit it.
On Sunday, I was pretty certain that there was at least one more shooter, but with things I learned on Monday, I could see it being just whoever it was on the roof, although I still believe that he couldn’t have done it without inside intel, and maybe logistical help from several law enforcement officials.
But a lot of people who were there, on the ground and close to the action are still convinced there were multiple shooters. Whether any of them have the knowledge and / or experience to actually understand what they saw and heard, I couldn’t say. Such events can be very confusing even to people who are combat veterans.
There were about three interviews I saw claiming there was a shooter in the water tower, for example. But given the way the mind works, they could have easily heard the shots, turned to see a water tower, and made the assumed connection that must have been from where they came. The mind could go as far as fabricating that evidence in mind’s eye with certainty if it was the belief of the person. Which is why witness testimony is often unreliable.
The incontrovertible fact is that MUST SECURE areas were never secured.