Don't know. They refused to release the video citing not wanting to play into stereotypes, whatever that means, then changing the reason to the age of the offenders. No way for me to tell.
One reason I like to carry my Cold Steel Voyager XL Tanto with its big 5.5" blade. In that situation with that close of contact a knife furiously slashing and jabbing would be more effective IMO than a gun with limited ammo. Also these teens most likey would have scattered at the first thug dropping to the ground.
I don't care who you are and if you are a teen. If you wanna act like a criminal than I'll treat you like one.