The gunman who killed himself after fatally shooting one of six girls he held in a high school classroom methodically selected his hostages and had sexually assaulted some of them during the ordeal, the sheriff and a witness said Thursday.
"He did traumatize and assault our children," Park County Sheriff Fred Wegener said. "I'll only say that it's sexual in nature."
Wegener identified the suspect as Duane R. Morrison, 53, and said was he from the Denver area but had been living in his car. He said investigators had not established any previous connection between him and the hostages.
State records showed he was arrested in July in the west Denver suburb of Lakewood on a charge of obstructing police in another suburb. He was also arrested for larceny and marijuana possession in 1973.
Reached at their home in Tulsa, Oklahoma, Morrison's stepmother said she and her husband, Bob Morrison, "have no record of him being, having any trouble before."
"We just know the way he was raised," Billie Morrison said, declining to elaborate. She said the last time she saw him was three to four years ago.
Authorities said Morrison had let four of the hostages go before an elite police commando team stormed the Platte Canyon High School classroom where he had been cornered Wednesday.
The gunman fatally wounded one of the girls and killed himself as the deputies charged in. The other girl escaped.
The victim was identified by acquaintances and a co-worker as 16-year-old Emily Keyes, shown in a yearbook photo as a smiling blonde who played volleyball and was on the high school debate team.
She was pronounced dead at a Denver hospital after Wednesday's standoff, which reminded many people of the 1999 massacre at Columbine High, less than an hour's drive away.
"This is something that has changed my school, changed my community," said Wegener, a 36-year resident of Bailey. "My small county's gone."
Wegener said Morrison made few demands. "Most of the demands were, 'Leave me alone, get out of here,'" he said.
Asked about his decision to storm the classroom, Wegener said:
"Being a sheriff in a small community, knowing all the parents, knowing the kids - my daughter graduated last year, my son's a junior here - it is very difficult. Because I'd want whoever was in my position to do the same thing. And that is to save lives," he said.
Morrison began the takeover by ordering students to line up at the chalk board as he tapped each with his gun and told them to stay or go, a student in the classroom said.
Cassidy Grigg, 16, said the man walked in, fired a warning shot at the floor and ordered the students to line up. He told some to leave and others - all girls - to stay.
"You could tell that he wanted the females," Cassidy said on NBC's "Today" Thursday. "He tapped me on the shoulder and he told me to leave the room. I told him, 'I don't want to leave.'"
"He told me that if I didn't go then he would pretty much kill me," Cassidy told ABC's "Good Morning America." He said he wanted to stay "because I'm sure the girls would have felt more support if there would have been some males in the class with them."
No one recognized the man, who seemed to be dressed as a student, Cassidy said.
"He was just an old guy who came on a mission, and I think he got what he wanted," he told "Today."
"We are a community in mourning," schools superintendent Jim Walpole said. "Our thoughts, our prayers are with our students, staff and their families. Especially the family of the student we lost."
Residents gathered quietly Thursday morning at the Cutthroat Cafe, where Keyes had been a waitress for about two years, to grieve and remember, said Bobbi Sterling, a waitress and cook there.
"It's very sad here. You know, the family lost their daughter but as a community, we lost a child," she said. "We're just sitting here, numb and in shock. We're all just kind of stunned. People are here for mutual support."