Jeremy Steinke sat quietly Monday as a judge officially sentenced him to the automatic minimum prison term of life with no chance of parole for 25 years for killing his girlfriend's parents and younger brother in Medicine Hat, Alta.

Calling the fatal stabbings "horrific and unspeakable," Court of Queen's Bench Justice Adele Kent handed down three life sentences, to be served concurrently.

On Dec. 5, a jury found Steinke, 25, guilty of three counts of first-degree murder.

His former girlfriend, who was 12 at the time of the April 2006 killings, was previously convicted of the same charges and is serving a maximum youth sentence of 10 years in a psychiatric facility.

'I will never understand why she was taken. I will never understand the works of sick, twisted minds, but I do understand forgiveness.'—Victim impact statement by slain woman's brother

The slain mother's brother travelled from Ontario for the sentencing hearing in a packed courtroom, and read a victim impact statement offering forgiveness because he said his sister would want it that way.

The relatives and victims cannot be named to protect the identity of the girl, now 15.

"I will never understand why she was taken. I will never understand the works of sick, twisted minds, but I do understand forgiveness," the brother said. "So what is for [her] sake and the thought of deep love for my sister who I know is watching over us now, that I extend forgiveness."

Crown prosecutor Ramona Robins read four other emotional statements from relatives of the slain couple and their eight-year-old son in court.

They outlined how the couple's parents and siblings are still in counselling, how they're still angry and how they shed tears daily.

"This crime has been horrific and devastating," wrote the slain mother's sister.

"I cannot eat, I cannot sleep. I've already started counselling to help me get through this crime. It is great sadness in my life knowing I will never see my sister, brother-in-law and nephew again."

Killer 'extremely' remorseful

Steinke and the girl plotted to kill her parents, who objected to their relationship, and then run away together. The two were arrested in Leader, Sask., the day after the murders.

"He said he was extremely remorseful," said defence lawyer Alain Hepner, who spoke for Steinke. "If he could take it back, he would, but he just couldn't speak. He actually did say those things.

"I think it's an apology. I definitely think that's what it is."

Jeremy Steinke's sentencing was held in Medicine Hat, Alta., to give the community some closure, said the Crown. (CBC)

Steinke's mother, Jacqueline May, wept as she sat with several relatives. Hepner said they too have been devastated.

Steinke, wearing blue overalls, did not look up from the prisoner's box during the proceedings. When the judge asked if he had anything to say before she handed down the sentence, he shook his head.

Submissions made at the sentencing hearing become part of the official record. That information will be reviewed by a parole board if Steinke ever applies for parole.

Although the trial was held in Calgary, the Crown asked for the sentencing to be moved to Medicine Hat, a city of about 57,000 people.

"A lot of people knew the family members or had some relation of course through school or work and it was important to see the closure of it. It was a terrible tragedy and our community needed to see it closed. And I think that's what was accomplished today," said Robins on Monday.

Outside the courthouse, the brother read a prepared statement to reporters:

"Our family wishes to thank the community of Medicine Hat for their prayers, their support. Especially like to thank the prosecutors, the police services, and victim family services for their outstanding work and I hope that the media will now leave us alone. We haven't said much in the past and we're not going to say much now. Thank you."

With files from Bryan Labby, Scott Dippel, the Canadian Press