IDAHO FALLS, Idaho (AP) — A Pocatello man police say killed his girlfriend at a party while in the process of threatening a 16-year-old boy with a gun has pleaded not guilty to a series of charges.

The Idaho State Journal reports that 26-year-old Kevin McQuilliams pleaded not guilty Monday in 7th District Court to involuntary manslaughter. He also denied charges of aggravated assault with a deadly weapon, unlawful possession of a firearm, use of a firearm in the commission of felony and an enhancement for committing a felony with the intent to promote gang activity.

Police say McQuilliams killed 34-year-old Annarae Ponce on Jan. 1 at a house party in Idaho Falls. Witnesses say an altercation began when a group of people showed up and McQuilliams fired his gun, mistakenly killing Ponce.