Police are continuing their search for a driver and the province's Special Investigations Unit is involved after an unusual sequence of events — including a wrong-way pursuit, a serious head-on collision that injured a woman and the subsequent theft of a police cruiser — unfolded Friday night near Brampton.

Ontario Provincial Police say three people were injured after a vehicle refused to stop when flagged on the eastbound Highway 407 near the 410, then went the wrong way on a ramp and crashed into a second vehicle.

The first vehicle was fleeing an OPP cruiser at the time of the collision that seriously injured a 37-year-old female passenger in the second vehicle. According to SIU spokesperson Jason Gennaro, the injured woman underwent surgery at St. Michael's Hospital earlier Saturday.

Two children that were passengers in the fleeing vehicle, aged seven and three, also suffered minor injuries.

After the head-on collision, the driver of the fleeing vehicle got out of the car and stole a cruiser parked at the scene of the incident.

The OPP say the urgency of the situation after the collision may have contributed to the driver being able to commandeer a police cruiser.

"Obviously we need to take care and take precautions for our vehicle … so that it is secure at all times," said Sgt. Kerry Schmidt.

"When we've got a head-on crash right in front of us, we're going to get out and respond immediately," he added.

Theft suspect

The police vehicle was later found abandoned in a condominium parking lot on Eglinton Avenue northwest of Winston Churchill Boulevard in Mississauga.

Schmidt says the OPP knows the identity of the driver who stole the cruiser, but they do not have anyone custody.

The SIU is called in whenever there is a report of death, serious injury or sexual assault involving police. It says five investigators, two forensic investigators and a traffic reconstructionist have been assigned to the case.

Investigators are urging anyone who may have witnessed the incident to contact the lead investigator at 1-800-787-8529 x2290.