How can one tell if these thugs haven't already been arrested? Mug shots listed somewhere (having to sort mugshots next to pictures in gear ain't easy)? Must admit that whole video was full of people I wouldn't trust to go bat crazy. Sorry no help here, but that crowd would not be somewhere I would want to remain, too much energy with no positive direction. Shouting obscenities, just total chaos.
Don't get me wrong, there may be a time and place to do these things, that was not it. Again, just a mob, with no direction, probable filled with instigators and people weak to being lead into traps. You get into a group like this, bad things will happen.