Police released more details of a grisly murder-suicide at a Wyoming community college, saying a man shot his father in the head with a bow and arrow in front of a computer science class not long after fatally stabbing his father's live-in girlfriend at their home a couple of miles away.
Computer science instructor James Krumm, 56, may have saved some of his students' lives by giving them time to flee while trying to fend off his son, Christopher Krumm, 25, of Vernon, Connecticut, Casper Police Chief Chris Walsh said.
"I can tell you the courage that was demonstrated by Mr Krumm was absolutely without equal," he said, adding that his actions could offer some measure of comfort to those affected by the killings.
He said police still were trying to figure out what motivated Christopher Krumm to attack his father and girlfriend, 42-year-old Heidi Arnold, a maths instructor at the college.
Ms Arnold was found stabbed to death in front of the home she shared with James Krumm.
After shooting his father with the arrow, Christopher Krumm stabbed himself, then fatally stabbed his father in the chest in a struggle in the classroom, Mr Walsh said.
Police arrived to find James Krumm dead and Christopher Krumm barely living; the younger Krumm died soon after students fled in a panic. Authorities locked down the campus for two hours.
Police began getting reports about the attack on Ms Arnold soon after they responded by the dozen to the attack on the campus of Casper College.
Christopher Krumm had smuggled the compound bow - a type much more powerful and effective for hunting than a simple, wooden bow - onto campus beneath a blanket, Mr Walsh said.
He said Krumm also had two knives with him and the knife used was "very large".
"It's one of those situations you don't think is going to come home. It's not going to happen here," Mr Walsh said.
Ms Arnold died of multiple stab wounds. Her body was found in the gutter of her street. Evidence suggested much of the attack occurred outside the home, Mr Walsh said.
Christopher Arnold had recently driven to Casper from Connecticut and had been staying at a local hotel. He had no significant history of encounters with police.
Police were uncertain what went awry in Christopher Krumm's relationship with his father.
"It's difficult to say. I don't think it was very close," Mr Walsh said.