There's much more to it.
Montreal North now is in a certain 'gang-war' which the Italian mob is included. All the shops that were destroyed were Italian shops, except for 1.
This Croat I know who lived down the street of the riots said the next day after the riot. 5 Escalades from NYC including some with Italian flags were spotted entering the area. As you know, the Italian mafia in Montreal has close ties with the families in NYC, not saying that's what it is with those Caddies, but you catch my drift.
As for the cop. It was a female, who probably felt intimidated and pulled the trigger too quickly. If she was a big 300 lbs man, believe you me. He wouldn't have been as quick to pull the trigger.
Expect a lot more violence once the 2 cops get acquitted.