Yes
now, time for the tin foil hat:...go here to time mark 14:21 - community center roof, 488 yds away - and in line with rooftop and with stage. 488 yds is about 1500 ft. The internet says 600 yds is about the max range some, not all, ar-15 models can shoot with accuracy. So it could be, if there was a second shooter, something other than a 15 may have been used at that distance. That can be answered by what bullets were found. I'll leave that with the tin foil hat folks.