Montreal police shot a man in Old Montreal on Friday afternoon, who died after being sent to hospital.
It began in a building on Rene-Levesque and St-Urbain, when two men had an altercation and one of them, a 37-year-old, was stabbed.
The police were called, but by then the suspect had left the scene.
He was trailed by citizens, who directed police to him.
Officers caught up with him in an alley behind the Old Brewery Mission in Old Montreal - that led to a confrontation, said police spokesperson Daniel Lacoursiere.
"At a certain moment it seems that the suspect made a threatening gesture towards the police officers. The suspect was shot at least once in the upper body."
The stabbing victim was expected to survive.
Officers involved in the shooting were also treated for shock.