The SIU is investigating the actions of Elgin OPP after a driver was arrested for going the wrong way on the 401. 
A 20-year-old Plympton-Wyoming man was charged with almost a dozen offences, including impaired driving, after being pulled over near Dutton earlier this week.
Authorities say the man was injured while in police custody, which led to the SIU invoking its mandate to investigate any incident involving police that involves someone being hurt or killed.
The suspect was taken to hospital for an undisclosed injury and treated.