Police anticipated ‘worst-case scenario’ by deploying sniper at St. Patrick’s Day party, says former officer

A St. Patrick's Day party in Waterloo, Ont., left, is seen next to an image of a police sniper in this combination image.

The sighting of a sniper on Saturday during St. Patrick’s Day celebrations in Waterloo was met with fear and shock by some, but one policing expert from Wilfrid Laurier University says this is a proactive measure designed to keep the crowd safe.