The province's Special Investigations Unit has been called in to probe a crash that forced the closure of the eastbound lanes of Hwy. 401 near Ingersoll for several hours.
Just before midnight Thursday, Oxford OPP tried to pull over a vehicle that was heading east near Foldens Line. When the vehicle was pulling over, it became involved in a three-vehicle crash.
Four people from one of the vehicles and the driver of another were taken to hospital. An 18-year-old woman is in critical condition, while the other four were treated and released.
The eastbound lanes of Hwy. 401 were re-opened around 9am Friday.