The Alberta Court of Appeal has added three years to the sentence for Allan Shyback, who was convicted for strangling Lisa Mitchell and entombing her body in the basement of the home they shared.

Shyback was originally charged with second-degree murder in Mitchell’s death but was convicted of manslaughter in May 2017.

Mitchell was last seen at her home in Ogden in 2012 but her body was found two years later inside a plastic tub that had been buried inside the wall of the home.

The details of Shyback’s involvement in the case were only discovered following a Mr. Big operation orchestrated by undercover officers with the Calgary Police Service.

He was sentenced to seven years in jail for Mitchell’s death; five for manslaughter and two for interference with a body.

The Crown had been seeking a total sentence of 13 to 15 years (10 for manslaughter and three to five years for interference with a body) for Shyback and appealed Justice Rosemary Nation’s sentence decision in September 2017.

The Alberta Court of Appeal granted the Crown’s request on Thursday, saying that the trial judge erred in her decision in regards to the manslaughter sentence, saying that it wasn’t enough to match the gravity of the offence and Shyback’s responsibility.

As for the sentence for interference with a body, Justice Nation concluded that there were no aggravating or mitigating circumstances in the offence but the Court of Appeal says she did not take into account the obvious aggravating factors set out in the sentencing court.

They said that the fact that Shyback led Mitchell’s relatives to believe that she had abandoned them without reason or explanation and his deception further made them believe there was the possibility that she may return.

Once Mitchell’s body was discovered, the Court of Appeal said that the heartbreak of her death was enhanced for her family members, particularly for their children, when Shyback knew her body was entombed in the basement.

The Court of Appeal therefore upheld the Crown’s appeal and imposed a sentence of seven years for manslaughter and three years for interference with a body.