While contending that the other guy started it, a 63-year-old man has admitted that he fatally shot a Twin Cities man at an employee Christmas party at a popular North Shore resort.

A jury trial scheduled to begin Monday in Cook County District Court has been canceled now that Kirk L. Bigby, 63, of nearby Silver Bay, has pleaded guilty to second-degree unintentional murder in the killing of 35-year-old Marcus L. Roberts, of Bloomington.

The plea deal calls for a sentence ranging from 10⅔ to 12½ years. With credit for time in jail since the shooting, Bigby’s imprisonment could be anywhere from 6 to 7¼ years, followed by the balance on supervised release. Sentencing is scheduled for Aug. 9.

Roberts was at the Bluefin Bay resort in the small town of Tofte on Dec. 9, 2015, with a casino gambling party rental company when he was shot outside shortly after midnight. The rental company was providing entertainment for the annual Christmas party being held for the resort’s employees.

As the party was coming to an end, several people stepped outside from the resort’s Bluefin Grille, and that’s when Bigby “came into physical contact” with Roberts and shot him with a handgun, the Sheriff’s Office said in a statement soon after the killing.

In a court document outlining details of the plea deal, Bigby acknowledged that “intoxication is not a defense” for killing Roberts and that he was waiving his right to claim self-defense. However, the filing continued, “I am still able to argue that the victim was the first aggressor.”

The Sheriff’s Office said Bigby, who delivered firewood to guest rooms, had a government-issued permit to carry a firearm at the time.

Resort owner Dennis Rysdahl said there had never been a violent crime at Bluefin Bay in his 32 years there.

Roberts, who attended Minneapolis South and Redwood Valley High School, was the father of six children and had seven siblings.