Gunman or psychopath as I'd like to describe this guy, is right behind them and you can see the gun going off towards her and she starts screaming.
Why does the US have so many psycho's like this? I'm not going into a gun argument because that is redundant but this is straight up cold-blooded murder.
I've seen alot of bloody videos but those screams will always stay in my mind. I'd advise you not to watch it if you do not want to listen to them.