A 21-year-old woman is dead after a crash in the area of Quaker Road and Rice Road in Welland.
Officers were called to a report of a single vehicle crash at around 1 a.m. on June 1.
When officers arrived the woman was out of the car seriously bleeding.
She was sent to hospital and later died of her injuries.
The Special Investigation were called to the scene and are continuing the investigation.
The SIU is called to investigate reports involving police where there has been a death of a serious injury.
It is still unconfirmed what caused the crash, or how police were involved.