They had an actual video of the shooting on AOL, but you could only hear the gunfire, not see people getting shot. It was fully-automatic (machine gun) fire and they had to be using drum mags or something because a normal AR15 only shoots 28 rounds and you can hear a continuous stream of gunfire of maybe 100 rounds.
It does sound like he was using drum type magazines.
Horrible tragedy... amazingly fast response from the police... prayers for all involved.