The mother of a young man gunned down near Yonge-Bloor subway station urged a judge Wednesday to impose a "tough sentence" on the shooter.

"No matter what sentence the shooter gets, it won't be as devastating as the sentence he meted out to Gabriel — or to me when he shot my only child," Kelly Whetter said inside a downtown courtroom while delivering her victim impact statement.

The single mother lost her only child Gabriel Nikov, 18, when he was shot six times in the back outside the Tim Hortons on Yonge Street, just north of Bloor Street, as the sun was setting on April 13, 2016.

During the second-degree murder trial, jurors were shown surveillance video that showed Nikov involved in an argument with then-22-year-old Bradley Cheveldayoff outside the coffee shop. The altercation, though it lasted only seconds, became physical, with Nikov throwing a couple punches before Cheveldayoff broke away and began running down Yonge Street

Nikov turned to walk away before Cheveldayoff returned and shot him six times in the back.

Cheveldayoff was convicted of the lesser offence of manslaughter — a finding that Whetter said "sickens" her.

"Since when is it manslaughter to unload six bullets into the back of someone who is walking away from you?" she said.

Whetter was one of more than a dozen people to deliver victim impact statements.

"My life was torn apart by six bullets," she said told the courtroom.

"Some days I'm unable to leave the house or do basic tasks. Some days I throw up from the stress and the grief, and my body feels like it's sick and dying.

"Some days I'm destroyed until I feel the love of God and Gabriel, and Gabe tells me, 'Don't let my murder kill us both.' I won't deny that I have a stash of pills set aside, though, just in case the pain gets to be too much and being alive gets to be too hard. I can't believe I'm even saying this out loud, but it's the truth."

Many of the victim impact statements referred to the effect the crime and subsequent incidents of gun violence in the city have had on their sense of safety.

"The decision of a reckless gun-toting individual has destroyed a family forever. A mother has become childless because of a selfish act, by someone who had no regard for human life," wrote Anne York, a coworker of Whetter. "How many families must be broken because of gun violence? How many people must live in pain before anything is done....This violence can happen to anyone's child. These shooters are becoming too brazen now, with daylight shootings in crowded areas and playgrounds. Please help stop the hurt by making the right decision."

The Crown is expected to argue for a prison sentence of 18 to 19 years. The defence is expected to ask for 12 years.

Nikov's childhood nanny, Erica Glossop, submitted a victim impact statement as well.

"Gabe was a gentle kid, who stood up against injustice. In the end he did what he was always told to do — walk away when someone is bullying you," she wrote.

"May his life be a blessing and may his passing be a constant reminder that we need to do more to stop the scourge of guns and violence in our city and amongst today's youth across this country."

Katy McDevitt, the mother of one of Nikov's friends, described Nikov's funeral, packed with hundreds of teenagers.

"The boys got to me especially — all those tall boys, on the verge of manhood, whose understanding of the world suddenly included the ugliest lesson about mortality I can imagine: that the world is hostile, that in an instant a stranger with a gun can cut you down," McDevitt wrote.

"Murder hands a literal lifetime of pain to everyone who survives the victim. This is not something you 'get over.' Not ever. Please don't think it is."

"That's the reality of murder: it's a single act of violence that wound enormous numbers of people," McDevitt continued. "And the wounds we sustain never fully heal, so we can never fully recover. That's the horrifying truth — and because of one person with a gun, it's my reality and my son's reality...and the reality of hundreds of other people; I hope it's never yours."

Nikov's friend, Rebekah Johnson, described learning of the homicide while away for university.

"I wanted to run home to Toronto but in reality, my view of Toronto as 'home' changed that day. It would always be tainted for me, the city where I spent running around with Gabe would always be where he was taken from my life," Johnson wrote.

"Another difficult layer of this incident for me is having a hopeless feeling walking down the street knowing there are people that feel comfortable enough to walk around armed and ready to kill. I find myself walking down the streets of Toronto feeling colder and constantly threatened. The city that Gabe and I grew up in has changed for the worst, and taken away Gabe's potential to change it for the better as he had done during his short life."

Nikov was remembered in various victim impact statements as a fierce intellect with sharp wit, an incredible sense of humour, and as someone who stood up for his friends.

Nikov's friend Taylor Railey, who is studying criminology, vowed to contribute to reducing violence in Toronto "in any way I can."

"It was a heartbreak for me and my family to know he was shot in a senseless act," wrote Sonie Prince, who knew Nikov since he was a baby. "How to make sense and continue to live in a good Toronto requires a lot of contemplation and rethinking of my new world."

Whetter's friend Sonya D'Cunha wrote that the impact of Nikov's death "is undeniably all the more terrible because of the way in which he was taken. It was an act of cowardice and brazen inhumanity. In the city that we call home. When he was out like any other teen in the city, to hang out with his friends. Living his life like we all do, like our kids should be able to do. With people around on the city streets doing what every citizen should feel safe to do, being out for a good time."

To Nikov's mother, D'Cunha wrote: "Kelly, my heart is with you. I hope that this round of justice brings you some of the peace you deserve. I also hope that there will be true change in the climate of gun violence that is plaguing our city, our world, our lives."

Since her son's death, Whetter has become an advocate against gun violence through an organization called Communities For Zero Violence.

She told court Wednesday she has developed a scholarship in Nikov’s name with the money she saved for his education. That money, she said, will go to "young people who might be on the verge of making terrible choices and messing up their lives — and other people's lives. I want to help them put down their guns and pick up an education."

The sentencing hearing is scheduled to continue Sept. 20 with arguments from the Crown and defence lawyers.