Quebec's police watchdog has launched an investigation after a motorist, allegedly fleeing from police in one of three cars stolen overnight, caused a multi-vehicle collision in a Montreal suburb.

The Bureau des enquêtes indépendantes (BEI) says the three-car collision occurred at 7 a.m., leading to the closure of Curé-Labelle Boulevard in Blainville, Que.

The alleged driver of the stolen vehicle was transported to hospital in critical condition, while the occupants of the other vehicles sustaine…