The SIU is investigating the death of a 40-year-old man in Waterloo.
Waterloo Regional Police say they were called to Northfield Drive West at the bridge overlooking Highway 85 just before noon on Tuesday.
They were responding to a man in distress who was sitting on the overpass.
A short time after officers arrived on scene the man fell from the bridge.
The northbound lanes of the highway were closed for several hours while emergency crews were on scene.
The SIU were notified and have invoked their mandate.
They investigate all incidents of serious injury or death involving police.
