An Edmonton man admitted Friday to killing his two young sons on an unsupervised visit in a northside townhouse two years ago.

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Edmonton police stand outside the Abbottsfield home where the bodies of two boys were found Dec. 20, 2010. (CBC)

Jason Cardinal, 33, pleaded guilty to two counts of first-degree murder at the Edmonton Court of Queen's Bench.

He now faces at least 25 years in prison with no chance of parole.

Cardinal's sons, aged six and three, were found dead in an Abbottsfield home on Dec. 20, 2010, 10 hours after their mother and a family support worker went to pick them up following a unsupervised weekend visit. 

When no one answered the door, they called police who obtained a court order to enter the home.

In an affidavit for a search warrant, police said they found Cardinal lying on the bed with his sons on either side of him.

The boys had bruising on their necks and Cardinal, while alive, had deep cuts on his arms. The court heard that Cardinal had planned for at least two weeks to kill himself and the boys.

The boys' mother, who can't be identified, has called for a public inquiry into the deaths.

"I consider him the weakest coward I've ever known," she said. "For him to take my sons' lives — I don't understand why he just didn't take his own if he was so miserable."

Cardinal had been allowed unsupervised weekend visits with the boys even though he had lost custody of the children earlier in the year over concerns over his mental health.