A heavy police presence closed Kempenfelt Drive in Barrie on Saturday afternoon.
Barrie police taped off an area near Nelson Square.
City police say the Special Investigations Unit (SIU) has taken over the case.
No other details have been released.
The SIU could not be reached for comment.
The SIU is an independent government agency that investigates incidents involving police in which someone is injured or killed, or an officer is accused of sexual assault.
