A Toronto man who brutally murdered his ex-girlfriend and then carved up her body and scattered the pieces to cover up his crime may not have acted entirely alone, an Ontario Superior Court judge said Friday in sentencing him to life in prison with no parole eligibility for 18 years.

While the jury found Chun Qi Jiang was the one to fatally stab 41-year-old Guang Hua Liu two years ago, evidence presented at trial suggests his late mother helped in the cleanup, Judge Gisele Miller said in her decision.

"It may well be that his mother assisted him," despite the Crown's position that Jiang was the sole perpetrator, she said.

Jiang was found guilty in June of second-degree murder in the grisly slaying, a verdict that carries an automatic life sentence without parole for 10 to 25 years. Prosecutors had pushed for 20 years before he could apply for parole, while defence lawyers proposed 15.

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Jiang was found guilty in June of second-degree murder in the grisly slaying of Guang Hua Liu, above. (Peel Regional Police/Canadian Press)

"Nothing in the sentence can bring Ms. Liu back," Miller told the court. Rather, the ruling "is meant to express the community's repugnance for this conduct."

That Liu was killed in a "brutal attack" by a former boyfriend is considered an aggravating factor, the judge said, as are Jiang's efforts to cover his tracks by destroying evidence and desecrating her body.

However, the judge dismissed the Crown's argument that the attack showed "elements of planning," which would justify a longer period of parole ineligibility.

Miller said she factored in that Jiang had no prior criminal record or history of violence.

Jiang pinned the murder on his mother

Liu, a single mother of three who ran a massage parlour, had been caught in a love triangle that prosecutors alleged turned deadly after she rejected Jiang for his rival.

He was arrested in the weeks after her body parts began to surface in Toronto-area waterways and parks, triggering a massive investigation.

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Chun Qi Jiang is shown in a court sketch during his trial.

During his trial, Jiang pinned the murder on his mother, testifying the 66-year-old woman stabbed and dismembered Liu in a fit of rage over allegedly stolen jewelry. He admitted to helping her dispose of Liu's remains and cover up the crime.

His mother died of natural causes shortly after his arrest.

Jiang declined to address the court Friday but his lawyer, Kathryn Wells, said he maintains he did not kill his former girlfriend. She argued he could be rehabilitated in prison despite a significant language barrier.

Asked outside court whether her client would appeal, Wells would only say that Jiang "is considering his options."

Earlier Friday, Crown lawyer Brian McGuire said Jiang committed a horrific crime against someone who had every reason to trust him.

"This was an attack that was prolonged, it was persistent, it was savage, it was heartless and it was cowardly," he said.

Neither Liu's new boyfriend nor her family members were in court. Jiang has been barred from contacting them as part of his sentence.