Tensions between Montreal police and the citizens they are sworn to protect swelled Wednesday as demonstrators took to the streets to protest a shooting that killed an innocent bystander.

Patrick Limoges, 36, was on his way to work at a central Montreal hospital on Tuesday morning when he was hit by police gunfire. Police opened fire in the street as they pursued a homeless man who was slashing garbage bags with a knife.

The homeless man, 40-year-old Mario Hamel, was also shot dead by police.

While public local safety officials have defended the police and the shooting, the explanations have done little to defuse simmering tensions. Over the past years, other anti-police demonstrations have turned into mini riots, with vandalism often the end result.

Earlier on Wednesday, co-workers of Limoges gathered at the scene of the shooting and solemnly marked the death of their colleague. Flowers were left at the scene and a moment of silence was observed.

But later in the day, about 100 demonstrators dressed in black materialized in the streets.

On Tuesday, police were chasing Hamel in the moments before they opened fire, after witnesses reportedly saw him slashing garbage bags with a knife and throwing trash all over the street.

While a group of police officers were seen yelling at Hamel to stop, it is unclear what happened in the immediate moments before the shooting.

Authorities said Hamel died in the street.

Limoges was riding a bicycle on the other side of the street when police started shooting. He was only one block away from his hospital workplace when he was fatally wounded.

"When you come in to work, you come in to work -- not to die on a sidewalk," said colleague Gilles Girard, a colleague at the Hopital St-Luc.

"You don't imagine dying like that. A stray bullet."

Co-workers remembered Limoges as a courteous and diligent worker with a spotless, three-year track record at work.

Provincial police are now investigating the circumstances behind the shooting.

According to provincial records, 72 people have been killed or seriously injured by police gunfire since 1999.

One high-profile case was the death of Fredy Villanueva, who was an unarmed teen shot dead by police three years ago.

Quebec's public security minister, Robert Dutil, has defended police in the wake of the shooting, saying that officers only use their weapons in a small fraction of cases each year.

He said that out of 15,000 cops across the province, only 60 ever fire a gun.

"So it happened (with) only one of 200 policemen each year," Dutil told reporters in Quebec City.

"A police officer in his career is very unlikely to have fired a gun. What I'm trying to say is there's no pattern.

"I believe they're well-trained. I believe they're well equipped. I believe they do their best. Unfortunately, in a society like ours, this kind of thing happens. We wish it wouldn't."

With files from The Canadian Press