Video appears to show a fire fight.

Dude in the green t-shirt comes out from behind some cars, approaches the downed guy, gets on his phone to call someone, then runs toward the filmer when the mob approaches.

One of those on the ground, when asked if he shot the guy, say something out "green t-shirt" (listen carefully near end)

Some twatterer says he can hear green shirt say "i just killed somebody" on the phone as he approaches filmer.

You decide…