Two Calgary children "will be destroyed" when they learn they lived in the same home where their mother's body was entombed in cement after she was fatally strangled, said their grandmother at the sentencing hearing Wednesday for Allan Shyback, 40.

He was sentenced to seven years in prison. 

Court of Queen's Bench Justice Rosemary Nation gave Shyback five years for manslaughter and two years to be served consecutively for indignity to a body. With the time he's already spent in custody, he has about two years and 10 months left to serve.

"I would hope you would use your remaining time in prison wisely," said Nation. "You can return to be a contributing member of society but that future is in your hands."

Originally, Shyback was charged with second-degree murder but found guilty in May of the lesser offence of manslaughter. He had argued he acted in self-defence when he killed his common-law wife, Lisa Mitchell, in 2012.

He was also found guilty of indignity to a body for entombing Mitchell's body in cement in a corner of the basement of their home where he continued to live with their children.

Allan Shyback Lisa Mitchell

Lisa Mitchell and Allan Shyback were in an on-again/off-again relationship for a decade before she disappeared. (Facebook )

Several victim impact statements were read at the hearing including from Mitchell's mother, Peggy, who wrote that her grandchildren believe they will be able to live with their dad again. 

"They both think mom is an angel and dad is with the police," wrote Peggy Mitchell. "They are little lost souls."

Shyback was sentenced to five years for manslaughter and two years for the indignity to a body conviction.

In both his statement to undercover officers and in his testimony, Shyback said he panicked when he realized he'd killed Mitchell, afraid to call the police because he didn't want his children to be taken away.

Instead, he tried to cover up his crime by placing Mitchell's remains in a Rubbermaid container and cementing it into a wall in the corner of the basement.

Allan Shyback Lisa Mitchell body

Lisa Mitchell's body was found by police two years after she disappeared inside a plastic bin that had been covered by cement in a corner of the couple's basement. (Court exhibit)

Mitchell's family members spoke of feeling betrayed by Shyback in the months Mitchell was missing before charges were laid and her remains discovered. 

"He looked us all in the eye and knew how much we hurt and said 'well I hurt, too,'" said Sarah Mitchell, Lisa's sister-in-law.

Court heard Mitchell's grandmother Janet Amos slept holding a photo of her granddaughter every night since the day she went missing. She died in her sleep last year still holding on to the picture. 

Mitchell was last seen in Calgary in October 2012. An undercover police operation started in 2013 and ended with Shyback's confession and arrest in Winnipeg a year later.

Before her death, Amos penned a victim impact statement, writing that Lisa Mitchell "was a light in my life."

When Shyback testified in his own defence, he told the court he'd been the victim of domestic abuse for years and on the day of the fatal argument, Mitchell came at him with a knife.

The judge found Shyback was justified in fending off Mitchell but only until the couple fell to the ground.

Once Mitchell was overpowered and the knife was out of her hand, Shyback used "force that was more than necessary," the judge ruled.

Peggy Mitchell John Hebert

Staff. Sgt. John Hebert was in the missing persons unit when Lisa Mitchell disappeared in 2012. Lisa's mother, Peggy Mitchell, embraces the officer Wednesday after her daughter's killer was found guilty of manslaughter. (Meghan Grant/CBC)

At the sentencing hearing on Wednesday, prosecutor Jayme Williams proposed Shyback serve a 10-year sentence for manslaughter plus three to five years to be served consecutively for the indignity to a body conviction. Defence lawyer Balfour Der was looking for a five-year sentence; three for manslaughter and two for indignity to a body.

After the sentence was handed down, Peggy Mitchell said Shyback's actions "showed a little bit of remorse." She said she is "working" on forgiveness.

Shyback's two children live with Peggy and her husband. 

"The children are great, they're doing OK," said Mitchell, who didn't rule out a relationship between the kids and their dad in the future. 

"When they are ready, then it's going to be totally up to them," said Mitchell. "It's their lives, their dad; you can't take away someone's dad."