Hundreds of protesters marched the streets of Toronto Monday, calling for justice as they walked past the site where an 18-year-old was fatally shot in a standoff with police over the weekend.

Sammy Yatim’s sister and mother were among the crowd of demonstrators that stretched for more than a block. The teen’s mother was visibly shaken and barely able to speak. She was heard repeating her son’s name while reaching out for a photo of him.

The protesters began their march at the Yonge-Dundas square in downtown Toronto, chanting “Shame” and carrying signs such as “Patience before decisions and irrational thinking.”

Some of them angrily confronted police officers who were dispatched to monitor the demonstration.

Yatim was gunned down on a stopped 505 streetcar on Dundas Street near Grace Street just after midnight on Saturday.

Witnesses say they saw the teen holding a knife. By the time police arrived on scene, the streetcar had emptied.

Eyewitness accounts and video captured at the scene indicate police told Yatim to drop his weapon.

At least nine shots were fired. Yatim was taken to St. Michael's Hospital where he succumbed to his injuries.

Suspension with pay

The Toronto Police Association said the police officer involved in the shooting has been suspended with pay.

Association president Mike McCormack confirmed the suspension to CP24.

“He’s just overwhelmed by the magnitude of everything,” McCormack told The Canadian Press earlier.

An investigation has been launched by Ontario’s police watchdog, the Special Investigations Unit.

McCormack stressed that the public shouldn’t jump to conclusions before investigators gather all the facts surrounding the shooting.

“All we’re asking is to wait until all the information comes in, and then we can look at the officer’s actions appropriately and make the right decisions as it were,” he said.

The suspension follows a commitment by Toronto’s police chief Bill Blair that his force will do everything it can to determine why the teen was killed.

At a news conference on Monday morning, Blair said he had seen widely-circulated eyewitness videos of the incident and shares the public’s concerns about police conduct.

“I am aware of the very serious concerns the public has," Blair said. "I know that people are seeking answers as to what occurred, why it happened and if anything could have been done to prevent the tragic death of this young man. I am also seeking answers to these important questions."

According to the SIU, Yatim sustained multiple gunshot wounds. They say a Taser was also deployed.

Blair said his force would co-operate with the SIU, the arms-length provincial agency called in to examine cases of injury, death or alleged sexual assault in which police are involved.

"We will act as quickly as circumstances and the law allow," he said.

He also offered his condolences to the teen’s family.

"As a father, I can only imagine their terrible grief and their need for answers," Blair said.

The SIU has assigned six investigators and two forensic investigators to the case. The police watchdog said it will be interviewing 22 witness officers.

In addition to the SIU investigation, Blair said he will be conducting a separate probe to see if police protocols and training guidelines were followed.

“A full report of my review, actions and recommendations will be submitted to the Toronto police services board within 30 days of being notified that the SIU has reported the results of their investigation to the Attorney General,” he said.

Yatim’s death a “tragic situation”

Ontario Premier Kathleen Wynne described Yatim’s death as a “tragic situation.”

“My heart goes out to the family,” said Wynne, adding that she couldn’t comment on the shooting while it was under investigation.

Ontario Ombudsman Andre Marin also commented on the incident, saying his office will review the shooting to determine if it could lead to a wider probe.

"It's important that I look at it from a provincial angle, and that's what we're considering right now," Marin said.

"The government of Ontario...has the ability to issue guidelines and directions to police services on de-escalating conflict. We're going to have a discussion tomorrow to decide whether or not we should launch an investigation into whether or not those guidelines are sufficient."

A makeshift memorial for Yatim has been set up at the scene of Saturday’s shooting.

Messages left for the teen read: “You asked for help and we failed you,” and “You were everyone’s son, everyone’s child.”

In addition to the site of the shooting, protestors on Monday also briefly stopped at Toronto Police 14 Division, near Exhibition Place on Manitoba Drive.

Anyone with video footage or who may have information about the case is asked to contact the SIU’s lead investigator at 416-622-1965 or 1-800-787-8529, ext. 1965.

With files from The Canadian Press