A grieving mother says she's stunned by the sentencing outcome in her son's grisly death, and she wants answers.

In 2011, Wesley Hallam was fatally stabbed at a house party in Sault Ste. Marie.

He was then decapitated and dismembered.

On Thursday, Ronald Mitchell, Dylan Jocko and Eric Mearow pleaded guilty to manslaughter and offering an indignity to a human body.

Because of time already served, all three men will spend two years or less behind bars.

Sandra Hallam, Wesley's mother, said that's not enough, and accused prosecutors of dropping the ball.

"I know, sitting in those courts all this time, I know what happened. I know they killed him," Hallam said. "I believe in my heart they did it deliberately, and I can't see how they would reduce it to manslaughter and for what reason."

She said she'll continue to speak out in the media about what she considers to be a miscarriage of justice.

"The Crown's decided that my son was not worth anything," she said. "He was worth something to me and my family, and to his son. They did a grave injustice to all of us here."

Sault Ste. Marie police chief Robert Keetch said last week that he was disappointed with the sentencing outcome in Hallam's death.

Keetch has asked the Ministry of the Attorney General for an independent third-party review of the case.