GRAND MARAIS, Minn. — A Minnesota man will serve more than 12 years in prison for shooting another man to death during an annual holiday party for employees nearly two years ago.

Sixty-three-year-old Kirk Bigby, of the town of Finland, was sentenced Wednesday after pleading guilty in May to second-degree unintentional murder.

Bigby worked at the Bluefin Bay Resort in Tofte, a popular resort on the North Shore of Lake Superior. Authorities say he shot and killed 35-year-old blackjack dealer Marcus Roberts, of Bloomington, outside the resort restaurant where the party was held in December 2015.

Bigby at one point had maintained that he acted in self-defense. WDIO-TV reports under a plea agreement, prosecutors dropped a second-degree intentional murder charge.