UPDATE: Crash on Toronto-bound highway leaves one woman dead and another in critical

Provincial police say a 22-year-old woman is dead and a 19-year-old woman is in critical condition after a five-vehicle crash on a major highway west of Toronto on Saturday night.

OPP spokesman Sgt. Kerry Schmidt says the vehicles involved in the crash were on the QEW when a traffic slowdown caused a collision.

Twelve people were involved, with five suffering from minor injuries in what Schmidt is calling an absolutely horrific crash.

Images from the scene showed crumpled vehicles piled across multiple lanes with debris scattered across the road.

Police identify the deceased as Nicole Turcotte of Niagara Falls, Ont.

Schmidt says they're appealing for more info from bystanders in their investigation into the crash.

In another update Sgt. Schmidt said, "This crash happened as a result of what may have been an experience of road rage on the highway that did not involve the victims of this crash." 

Schmidt said that while a total of five vehicles were involved in the collision, there may have been a sixth vehicle that was indirectly involved, triggering a chain reaction.

"Investigators now believe that prior to this crash taking place, a vehicle similar to a Honda Civic travelling in the middle lane moved in front of traffic travelling in the left lane and slowed down, applied their brakes and did what they call a 'brake check'" Schmidt said.

"The driver behind that vehicle then slowed as well to avoid a collision, but the ensuing traffic behind these vehicles triggered a multi-vehicle chain reaction."

Schmidt said witnesses said the lead vehicle sped up after braking and then took off. That vehicle was last seen exiting the QEW at The West Mall, between Mississauga and Toronto.

Schmidt tweeted the suspect vehicle was a dark colour and had a recently registered license plate that may have included the letters #CE.