Friends and family of a slain Calgary couple and their grandson broke into applause as Douglas Garland was sentenced to life in prison with no chance of parole for 75 years.

Garland will die behind bars.

The decision was handed down in Calgary Friday afternoon by Court of Queen's Bench Justice David Gates after hearing submissions from lawyers and statements from family members of Garland's victims.

Garland, 57, was convicted Thursday on three counts of first-degree murder in the 2014 deaths of five-year-old Nathan O'Brien and his grandparents, Alvin Liknes, 66, and Kathy Liknes, 53, of Calgary.

"It is difficult to conceive a more cunning, cruel and horrific set of circumstances of assault, abduction, torture and murder," the judge said to Garland.

"The horror and the terror you visited on these three innocent people extends almost beyond the boundaries of ordinary human comprehension. The circumstances defy description."

Gates described the murders as "brutal and senseless and planned."

He said there were no mitigating circumstances offered at the sentencing hearing and said Garland offered no remorse or regret.

The degree of moral blameworthiness in this case is "very, very high," the judge said.

Garland showed no visible emotion in the courtroom as the sentence was delivered.

'I still fight the darkness': Nathan's mother

Earlier Friday, members of the slain trio's families presented impact statements.

"I still fight the darkness that threatens to take me down," said Jennifer O'Brien, Nathan's mother.

"When I leave here today, my wife and I will only go home to two sons," said Nathan's father, Rod O'Brien, choking back tears as he read his statement.

"T​hose who choose evil, they will get an eternity of evil," he said. "A life sentence on earth is nothing compared to what waits for you."

Crown prosecutor Vicki Faulkner read statements from Alvin and Kathy's son, Jeff, and Alvin's daughter Nancy.

It was a tense and emotional hearing. Faulkner fought back her own emotions as she read a question posed to Nancy by her son on his fifth birthday.

"Is the same thing that happened to Nathan going to happen to me too?" the boy asked.

'Evil' crime: Crown

Jeff Liknes wrote about his struggle to look past the hate and focus on love instead.

"This is not a life meant for anyone in the world," he wrote. "No one can relate; I lost everything I know and care about overnight."

Alvin's brother, Allen Sr., offered a brief message of thanks to the justice system and Garland's family for turning him in. It was Garland's sister, Patti Garland, who told police her brother drove a truck just like the one spotted on CCTV footage on the Liknes's street the night they disappeared.

Crown prosecutor Shane Parker refused to mention Garland by name, only referring to him as "the prisoner" in his submissions.

"I've prosecuted many murder cases," said Parker. "This is different ... it is without reason. Perhaps it's why this crime has rocked the city.

"It's evil."

Parker asked Gates to impose consecutive life terms so that the victims' family members don't ever have to get a notice of a parole hearing for Garland.

"Life for some is precious," Parker said. "To the prisoner, ending life with gratuitous violence was the end goal."

Garland "played out a violent fantasy" when he killed the family, said the prosecutor, who asked Gates to consider the youngest victim.

"Nathan — a whole life ahead. A superhero in training," he said.

"These acts display a character of evil; you can't rehabilitate evil," Parker told the judge.

Douglas Garland showed little expression throughout the trial and declined to speak when invited by the judge at his sentencing hearing. (CBC)

The jury deliberated for 8½ hours on Thursday before finding Garland guilty.

Gates told jurors they could recommend consecutive life terms, which would mean Garland would not be allowed to apply for parole for 75 years. After a short deliberation, 10 of the 12 jurors made that recommendation.

"The only way that one can, in fact, effectively give value to each life taken is by increasing the period of parole ineligibility," Markham Silver, a Calgary criminal defence lawyer and the co-chair of the criminal justice section of the Alberta Bar Association, told CBC News Friday.

"In this case, the only way you can do that is by giving consecutive periods of parole ineligibility."

Read updates and tweets from CBC News reporters who were in the courtroom. On mobile? Click here to see the live blog.

Garland's sentence ties him with two others for the stiffest sentences in Canada since the death penalty was abolished:

Justin Bourque was sentenced to life in prison with no chance of parole for 75 years for killing three RCMP officers and wounding two others in Moncton, N.B., in 2014.

Serial killer John Paul Ostamas was sentenced in 2016 to life in prison with no parole eligibility for 75 years for the killings of three homeless men on the streets of Winnipeg.

Defence lawyer Kim Ross told the judge Thursday he could look at the murders "as one continuous act" and give Garland three concurrent life terms, which would have allowed him to apply for parole after 25 years.

"He's trying to take it all in and digest what's happened," said Ross of Garland's reaction to the decision.

Ross and his co-counsel Jim Lutz did not call any witnesses to testify and wouldn't comment on the possibility of an appeal.

Jurors had heard earlier in the trial that Garland was angry at Alvin Liknes over a business relationship formed and broken years earlier.

The bodies of Alvin and Kathy and their grandson Nathan have never been found. The three family members were taken from the Liknes's home alive on June 29, 2014, then killed on a farm near Airdrie, north of Calgary, where Garland lived with his parents, according to the Crown's theory.

There was evidence presented at trial that Garland burned the bodies.

The search for Nathan and his grandparents ended two weeks after their disappearance when Garland was arrested and charged with murder.

Jurors heard testimony that DNA from all three was found on the Garland farm, including on a hacksaw and a meat hook.

Two small pieces of human remains — belonging to Alvin and Kathy Liknes — were also found on the property.

Calgary's police chief issued a statement on Friday praising the work done by investigators and offering words of support to the victims' family members.

"It is this ability to work together to support one another and to persevere through the most difficult of moments which reflects the strength of our organization," said Chief Roger Chaffin.

"This trial brings them no closure as they live every day with the void of a loved one, but we do hope the outcome brings them some measure of comfort."