The province’s police watchdog is appealing for witnesses following a collision involving a police cruiser that left a woman seriously injured in Ajax over the weekend.

Durham Regional Police said officers were responding to a call when they collided with a silver Lexus on Kingston Road West, between Randall Drive and Church Street South, at around 7:30 p.m. on Oct. 1.

The Special Investigations Unit (SIU) says three occupants from the Lexus were taken to hospital for treatment.

Police initially reported minor injuries but the SIU says a 64-year-old woman was later diagnosed with a serious injury prompting the SIU to invoke its mandate.

Four investigators, two forensic investigators and one collision reconstructionist have been assigned to the case.

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

The SIU investigates the conduct of police officers and other officials that may have resulted in death, serious injury, sexual assault and/or the discharge of a firearm at a person.