Those who were in the area of Hess and Market Street in downtown Hamilton may have heard a loud “popping noise” at around 10 p.m. on Wednesday night.
Hamilton police say the noise was caused by a flare gun that was discharged during a fight between a group of men.
No injuries have been reported and police say the men fled before they arrived at the scene.
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Hamilton Police Services say the Central Criminal Investigations Branch has taken over the investigation.
Anyone with information is being asked to contact Det.-Const. Alex Buck at 905-546-3816.
In Canada, it is illegal to fire a flare gun unless it is used exclusively for signalling or notifying distress.