Police chief stands by decision to deploy sniper at St. Patrick’s Day street party in Waterloo, Ont.

People walk along King St. N. for St. Patrick's Day celebrations.

The Waterloo Regional Police Service’s chief is standing by the decision to deploy a tactical officer to an unsanctioned St. Patrick’s Day street party in Waterloo, Ont., after sightings of what appeared to be a sniper were posted on social media.