ST. PAUL, Minn. (AP) - The Minnesota Court of Appeals has upheld a 40-year prison sentence for a Duluth man who pleaded guilty to suffocating his 13-month-old daughter.

Thirty-one-year-old Christopher Dennis Peterson pleaded guilty to second-degree murder in the July 2014 death of his daughter Layna. Peterson admitted he would place his hand over the girl's mouth and pinch her nostrils closed to stop her crying.

Peterson received a prison term nearly twice as long as the presumptive sentence. In a decision Monday, the appeals court said the district court did not err when it identified aggravating factors for the longer sentence.

St. Louis County prosecutor Jessica Fralich argued that the girl was particularly vulnerable, that the crime happened in the victim's zone of privacy and that Peterson treated his daughter with particular cruelty.