A 24-year-old ski lift operator who fatally shot the general manager of the Eldora ski area was determined to kill co-workers who weren't Christian, according to court records obtained Thursday. The documents, filed Wednesday in Boulder District Court, said witnesses told authorities that Derik Bonestroo walked into a building at work, fired a gun into the ceiling and said: "If you're not Christian, you're going to die." General manager Brian Mahon was shot and killed Dec. 30 at the ski area west of Nederland, Colo., in Boulder County. Witnesses said when Bonestroo asked Mahon's religion, Mahon said "Catholic" and Bonestroo shot him twice: in the chest and head. Mahon is believed to have died instantly. Other employees ran out the back door of the ski employee's meeting area and fled into the woods, describing an additional four to five shots being fired.Boonestroo fled the ski area in his car and then was intercepted and chased by a Boulder sheriff's deputy who happened to be in nearby Nederland when the 911 call came in. Boonestroo fired at the deputy's vehicle, hitting it several times, and finally pulled over on Highway 119 and began firing out his driver's side window.The deputy, a Boulder SWAT officer, returned fire after taking cover behind his vehicle. Authorities say Bonestroo was hit multiple times by the deputy's assault rifle before he fatally shot himself while sitting in his car, a few miles from the ski area. Chris Fiegel, a sheriff's detective, interviewed employees who were at the ski area's pump house for a staff meeting. He also interviewed other area residents who were confronted by Bonestroo. Bonestroo's "demeanor and tactical style clothing" indicated that he planned the showdown, according to court documents. Investigators said Bonestroo had a "drop-down magazine holster" strapped to his left thigh and a "drop-down gun holster" on his right thigh. They said he was clutching a Glock semiautomatic handgun in his right hand. Among the list of items confiscated from Bonestroo's apartment were medication and a dead cat that was stabbed several times, Pelle said. The cat was believed to be Bonestroo's pet. Interviews with friends and family member indicated Bonestroo recently had been suffering "significant emotional distress," but Boulder County Sheriff Joe Pelle said privacy laws prohibit him from discussing details of Bonestroo's mental state.