i'm no cyril wecht but it looks like first shot came from popo direction, hit a can and knocked it towards the bldg. then shots came from inside. and then schit tons more inbound.
The police was firing pepper spray "balls" and rubber bullets trying to disperse the crowd and enforcing a curfew that was in effect. That is what probably hit the water bottle. Still no reason to return live handgun fire at the police.
