This same video was already posted here at LF. These scumbags slapped a new video title on it and uploaded it again. They're clickbaiting off mass murder. I guess they're not alone.
Huh? Anyway, there probably was just one shooter. The two hotel employees were there in the hallway and would have seen someone else escape. And no evidence exists to indicate there were shooters at any other location.
Normally, you would assume they would be doing full crime scene workups of bullet impacts and trajectories, to trace the source of the bullets, to count the total rounds to match to the casings found in the room, match as many bullets as possible to the guns that fired them.
But this investigation seems so amateurish, I'm not confident that we can assume they are doing any of those things.