Ontario’s police watchdog is investigating the death of a female driver after two pickup trucks collided during a police chase in London early Wednesday morning.

The Special Investigations Unit (SIU) says preliminary information suggests that just after 2 a.m., an officer with the London Police Service observed a GMC Sierra of interest to authorities while on patrol in the area of Chesterfield Avenue and Thompson Road.

“The officer began to follow the Sierra. Shortly after, the driver of the Sierra took off at a high rate of speed,” the SIU said in a Wednesday press release.

“In the vicinity of Adelaide Street South and Thompson Road, the Sierra became involved in a collision with a Ford F-150. The female driver of the F-150 was pronounced deceased at the scene.”

The SIU says the three occupants of the Sierra – two men and one woman – fled the scene on foot following the collision.

“The woman was apprehended soon after and transported to hospital for treatment,” the release read.

It’s unclear whether or not the two men who fled from the Sierra have been apprehended.

The SIU did not disclose why the Sierra truck was of interest to police.

Three investigators have been assigned to the case, and the SIU is urging anyone who may have information about the investigation, including video or photos, to contact the lead investigator at 1-800-787-8529.

The SIU is an arm’s length provincial agency which investigates anytime police are involved in a death or serious injury.