The young man who murdered Charlotte Lafferty has been sentenced to life in prison with no chance of parole for 10 years.

Justice Louise Charbonneau ruled Thursday he would be sentenced as an adult, earning the life sentence in his first-degree murder conviction.

It's been just over three years since he brutally beat and murdered the 23-year-old mom in Fort Good Hope.

The man, now 21, appeared in court in a purple collared shirt and black pants with white socks. He sat silently throughout the sentencing.

The murder was one of the most brutal crimes ever described in a Northwest Territories courtroom.

"It's difficult to imagine a more brutal attack," Charbonneau said, calling Lafferty's killing a "senseless, gratuitous act that defies comprehension."

Charbonneau told the court that a youth sentence wouldn't be sufficient to hold the young man accountable for the severity of the crime, which happened when he was 17. She said he "intended to degrade" Lafferty and appeared calm after Lafferty's death.

"It's difficult for anyone to read or think about these circumstances," Charbonneau said. "This was a particularly violent and brutal beating, and it was prolonged. It included extremely contemptuous and degrading behaviour."

The court heard that Lafferty was kicked and beaten with a two-by-two stick. Her clothes were torn off. The young man urinated on her and sexually assaulted her with the stick. The attack went on for 20 to 30 minutes and left the young mom beaten beyond recognition.

The killer's name was initially protected by a publication ban under the Youth Criminal Justice Act.

That ban should have been lifted once the judge ruled he was being sentenced as an adult. The judge agreed to extend that ban temporarily.

The defence has applied to extend the publication ban permanently. That application will be heard May 11.