When he was 15 years old, he stabbed another 15-year-old to death. And for that, a young man was sentenced Monday to two-and-a-half years probation.

As part of his sentence, the now-18-year-old man, who cannot be identified under the Youth Criminal Justice Act, must also receive counselling and perform 140 hours of community service.

"He owes a debt to society and he will pay it back," Justice Katherine McLeod said. "He's a strong and healthy young man."

Klayton Wynter was killed outside Bramalea City Centre on April 23, 2011.

Court heard that Wynter and his friends had been robbing people in the food court. They robbed one group of a ring, a watch and $20 before approaching another group and leaving the mall.

The two groups of victims went after Wynter and his friends, confronting them outside the mall, court heard.

"Klayton became aggressive and punched two of the young men, the second being (the convicted teen)," McLeod said before rendering her sentence.

Wynter pulled out brass knuckles. His would-be killer pulled out a knife.

"The knife appears to be one of those utilized for removing the foil from corks on wine bottles," the judge said. "The knife was extremely small."

That blade hit Wynter three times, including once in the heart. Indeed, had it gone one millimetre to the left or to the right, Wynter would have required only a stitch or two, McLeod said, calling his death "an accident."

Questioned later by police, the teen who stabbed him couldn't believe it was his actions that caused Wynter's death, the judge noted.

"Clearly the fact that he had been responsible for the death of somebody was absolutely unbelievable to him," she said.

"There is no doubt that what Klayton and his friends were doing in the mall was criminal," McLeod said, noting that the "appropriate response" by the victims would have been to call police.

"Had that happened, nobody would have died, a family would not be mourning the loss of a bright young man and (the convicted teen) and his family would not be bearing the weight of Klayton's death on their souls."

In reaching her sentence, McLeod noted the profound effect Wynter's death had on his grandparents, who had put money aside for his education; his aunt, who helped raise him; and his mother, Cara Reid, who attended every court appearance for her son's killer with an admirable "degree of grace."

"The loss of a child when it is so preventable is something that I as a mother hope I will never have to endure," McLeod said to Reid. "The pain must be unbearable."

Speaking outside the courthouse, Reid tearfully said: "You try and move on, but there's only, you can only move on so much, right? The memory's always still in your mind every day."

But McLeod also noted several points about Wynter's killer: That he suffers from Attention Deficit Disorder, that he has been bounced between eight different schools and that he hasn't always had a father figure.

The teen has had a poor attendance record at school and, following his arrest for Wynter's death, was twice charged with assault. He entered into peace bonds for both charges.

McLeod noted the support of the teen's mother -- a mother who, after she was told what her son had done, was "so frustrated" by his actions, but "so loving" at the same time.

"It appears that the realization of his wrongdoing has been slow, but profound," McLeod said of watching the teen during various court appearances. "(He) must never forget that because of his thoughtlessness and his lack of insight into the full consequences of the action he has taken, he has caused the death of a young man who deserved to live the fullest of lives."

The teen's lawyer, Paul Erskine, called the probation sentence a fair one.

"The way he is now is not the way he was when I met him," Erskine said outside the courthouse. "He does have a lot of issues, there's no question about it. He needs a lot of help with some things, but I think this (sentence) is the one thing that will help him go in that direction he needs. I think he's got a bright future."

The teen was initially charged with second-degree murder, but later pleaded guilty to manslaughter. He served four months pre-trial custody and has been under a form of house arrest for two and a half years -- "significant" for anyone, McLeod said, but "extraordinary" considering the teen's age.

Still, Wynter's mother had been hoping for jail time.

She called his sentence "disappointing," before adding: "I guess justice is when you have to learn to live with something for the rest of your life, too, right? ... I have to live with it for the rest of mine, so he should, too."

Before releasing the teen from the courtroom, McLeod told him: "You're going to have to live with the memory of what you did for the rest of your life. The best way you can honour the memory of that young man is to be the best person you can be. Good luck."