Ontario’s police watchdog is investigating after a collision in North York early Saturday morning involving a civilian vehicle and an OPP cruiser left a 17-year-old boy with serious injuries and resulted in three other individuals being arrested.

At around 4:30 a.m., a York Regional Police helicopter operator observed a Honda Accord travelling west on Highway 401 at a high rate of speed, according to a news release issued by the Special Investigations Unit (SIU) on Sept. 3.

The SIU said the Accord got off at Meadowvale Road and stopped at a Circle K convenience store.

A YRP cruiser attended the location but the Accord, which was occupied by four individuals, fled the area and headed back onto Highway 401.

Officers with the Ontario Provincial Police (OPP) attempted to stop the vehicle but had no success, the SIU said.

The Accord exited onto Avenue Road and the OPP followed.

The SIU said the Accord then collided with an OPP cruiser in the area of Tresillian Road and Bombay Avenue.

It is unclear if the involved OPP cruiser was the one that followed the Accord off the highway.

One of the occupants of the Accord, a 17-year-old boy, fled on foot after the collision, the SIU said.

However, the SIU said he was located a short time later in medical distress and was transported to hospital with serious injuries.

The three other occupants were arrested and did not sustain any serious injuries.

The ages of the other occupants have not yet been released.

SIU investigation, North York

Photos from the scene show a burnt out OPP cruiser and a civilian vehicle with significant damage sitting in the middle of a residential roadway.

According to Toronto Fire, a vehicle hit a parked car after being pursued by police. Crews were called to the scene after at least one of the vehicles caught fire.

Mark Parry lives near the scene and told CP24 he heard police sirens approaching his neighbourhood early in the morning before he heard a "really loud bang."

"I heard the collision, there was an OPP vehicle right at the end of my driveway. There were some officers by the (civillian) car. They had one of the suspects, they were taking him forward to I guess the police car," Parry said.

"We had police dogs in the backyard, guys with serious weaponry, police officers, and they did a search. Helicopters lit up I think everyone's bedroom. This was a pretty intense activity," he added.  

The SIU has invoked its mandate and two investigators, three forensic investigators and one collision reconstructionist have been assigned to the case.

The police watchdog investigates all incidents involving police in which there is injury, death or allegations or sexual assault.

The SIU is asking anyone who may have information about this investigation, including video or photos, to contact the lead investigator at 1-800-787-8529 or online.