Longueuil police are looking a man they refer to as an important witness to a recent homicide.

An 18-year-old man was shot dead following a fight between two people on Grant Street in Longueuil around 6 p.m. Sunday evening.

Police say they don't believe the two people knew each other. The victim has been identified, but his name is not being released.

Police have released two photos, pulled from surveillance video, of a man they are trying to identify. They believe he has "key information" that could help them in the investigation, said spokesperson Marie Beauvais.

He is around 25-years-old, stands six feet tall, weighs about 150 lbs and has long dark hair.

In one of the photos, he is wearing a black hooded sweater, blue jeans, and is carrying a black sports bag.

Anyone with information about this man is being asked to call Longueuil police at 450-463-7211.