Hmmm, 22 year old enter police station, stabs two officers, is subsequently killed by one of the officers in self defense. Riots ensue. Clearly the 22 year old did nothing wrong.
One car got set on fire by a group of 20 people, they ran and split up when the police arrived.
That's not a riot. But they still should be punished like rioters, they obviously tried to start one.