It has been my observation that someone in the protest crowd (likely a paid, commie plant) fired a shot to provoke the police to return fire.
It is an old tactic, and is being used again, because it is very effective.
It is not much different than the Muslims shooting at soldiers and hiding behind children.
Yes, agitators often run and hide behind the rest following some provocative action. They make sure they’re not the ones that are going to receive any retributions.
...they (the communist agitators) actually hope that some really harmless ‘useful idiot’ type gets taken out. Better PR for gaining wider support for the movement. And of course most folks, thanks largely to the lame street liberal snooze media and leftist ‘educators’ in our schools, don’t know beans about who or what is behind these things. So it usually works out quite well for the revolutionaries.