Several people were taken to hospital following a multi-vehicle collision in Richmond Hill early Wednesday morning.
The crash, involving five vehicles, happened just before 7 a.m. on 16th Avenue just east of Leslie Street.
York Regional Police believe a pick-up truck crossed the centre median and collided with multiple vehicles.
York EMS say three people were transported to hospital, including the driver of the pick-up who was found without vital signs but was revived by paramedics.
He remains in hospital with life-threatening injuries.
The police K-9 unit was also called to the scene to look for people who may have been ejected from the vehicles but none were located.
The area is expected to be closed to traffic for several hours for the police investigation.
Police say they are trying to piece together what led to the crash and are urging any witnesses to come forward.