Police released more details Saturday 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 miles away.

Computer science instructor James Krumm, 56, may have saved some of his students' lives Friday by giving them time to flee while trying to fend off his son, Christopher Krumm, 25, of Vernon, Conn., 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 math instructor at the college. 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, 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 Arnold soon after they responded by the dozen to the campus attack.

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, 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," Walsh said.

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, 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," Walsh said.

Casper, population 56,000, is about 250 miles northwest of Denver and Wyoming's second-largest city after the state capital, Cheyenne. Wyomingites refer to Casper as the "Oil City" because it is a hub of the state's small oil industry.

Casper College is one of seven colleges in Wyoming's community college system. The campus was mostly quiet Saturday morning. Fathers and sons shot hoops in the school gym. A small group of drama students rehearsed a play in the school theater just across the street from the attack.

The building where the attack happened remained cordoned off by police tape that whipped in a brisk wind. A security guard let students back in, one at a time, to retrieve belongings they'd left behind.

Andra Charter, a 20-year-old sophomore, emerged with a coffee mug. She recalled hearing screams outside her biology class before getting word about what had happened.

"As we were walking out, there was a girl screaming, `There's somebody stabbing Mr. Krumm!'" Charter said.

No students were hurt in the attack.

Krumm was head of the college's computer science department. He was born north of London and also spent part of his childhood in Germany, according to the college website.

He held degrees from Casper College, a bachelor's degree and MBA from the University of Wyoming, and a master's in computer science from Colorado State University.

Arnold held a master's degree in mathematics from the University of Oregon and a bachelor's degree in math from University of California Davis.

The college planned a candlelight vigil and memorial service Tuesday.