Ontario’s police watchdog has been called in to investigate after a 36-year-old man was seriously injured in an overnight police chase in Pickering.

It happened at Brock Road and Bayly Street at around 3 a.m. Monday morning.

In a news release Monday afternoon, the Special Investigations Unit (SIU) said that the collision occurred after a Durham police officer attempted to stop a Mercedes-Benz on Bayly Street.

“The vehicle fled and the officer pursued in his cruiser,” the SIU said. “A short distance away, at Bayly Street and Brock Road, the Mercedes-Benz became involved in a collision with another vehicle.”

Images from the scene showed the overturned Mercedes lying on its roof on the roadway and another vehicle a short distance away with extensive damage.

A male passenger from the Mercedes was taken to hospital with serious injuries, the SIU said.

Durham police said a second male fled the scene and is outstanding.

The SIU is an arm’s length provincial agency called in anytime police are involved in a death, serious injury or allegations of sexual assault.

The SIU has assigned four investigators and two forensic investigators to the case. The agency is urging anyone with information to come forward.