A 19-year-old man was fatally shot by a Toronto police officer during a gun-related investigation in Mississauga early Thursday, prompting an investigation by the Special Investigations Unit (SIU).

The incident unfolded around 12:22 a.m. near Council Ring Road and The Collegeway, where officers attempted to stop a Mercedes carrying four occupants. During the encounter, three unmarked police vehicles were involved in a collision with the car, and one officer fired a single shot, killing the driver at the scene. The SIU confirmed two firearms were recovered, and there is no evidence that anyone else fired a weapon.

Three other occupants of the vehicle were arrested, while one was treated in hospital for minor injuries. A Toronto police officer also suffered minor injuries in the collision.

Although the SIU initially said the investigation involved a stolen vehicle, Toronto police later clarified the Mercedes had not been reported stolen. Investigators are continuing to examine the circumstances surrounding the fatal shooting.