The SIU is investigating a weekend accident in Hamilton when a pedestrian was badly injured after being hit by a speeding car.
It happened at about 10:30 Saturday night around Herkimer and Hess when police saw a speeding car and pursued it.
A pedestrian at the intersection was critically hurt with one of the cars involved smashing into a bus shelter on the corner and another car was also hit.
Three people from both vehicles received minor injuries.
The Special Investigations Unit becomes involved when a civilian is killed or injured as a result of police action.