Oh you are talking about the filmer, the girl who says 20 Asians jumped 2 of them, oh that is old news bro, no one believes her, just some made up story, this Asian is just some random school kid who go jumped bro. He ain't part of no gang that's for sure.
How do we know, did the case come to trial? Anyone can be part of gang, it may not be a formal named "gang". There is always a background story, and I have yet to hear the real deal, only what she has said...If it went to court, then it would have come out, unless there is a gag order due to the kids being juveniles.