The man who took six students hostage before fatally shooting one girl and then killing himself sexually assaulted his victims, Colorado police said.
"He did traumatize and assault our children," Park County Sheriff Fred Wegener told reporters at a news conference today. "I'll only say that it's sexual in nature."
The gunman was identified as Dwayne Morrison, 53, and police said he did not have any known connections to Bailey, Colo., where the shooting took place.
Morrison's motive remains unknown, and police said they were continuing their investigation.
Residents in Bailey, which is a short drive away from Littleton, where the 1999 Columbine shooting took place, are grieving the death of 16-year-old Emily Keyes, the Platte Canyon High School student who was killed in Wednesday's hostage situation-turned murder-suicide.
Morrison, police said, made few demands during the standoff.
"Most of the demands were, 'Leave me alone. Get out of here,'" Wegener said.
Some critics have questioned Wegener's decision to storm the classroom.
Wegener said that authorities had received indication Morrison was assaulting his hostages and that they had to take action.
"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.
Keyes played volleyball and was on the debate team at Platte Canyon High School.
She was pronounced dead at a Denver hospital after Wednesday's standoff. There was no known link between her and the gunman.
Fellow student Katrina Keller saw the suspect before going to class that morning.
"He was standing in a dark classroom, and I looked over and I thought he was a student," Keller said. "I looked him in the eyes, and I knew he was too old to be a student and my stomach turned over. … Then the bell rang, and I went to class."
Keller described Keyes as smart and outgoing.
Another student Cassidy Grigg believes the tragedy could have a positive effect on the small, mountain town of Bailey.
"I definitely think this is going to bring Bailey as a community closer together and to help anyone realize that anything can happen at any time," Grigg said.
But for now, the community is in shock and needs time to heal.
"We are a community in mourning," said schools Superintendent Jim Walpole. "Our thoughts, our prayers are with our students, staff and their families. Especially the family of the student we lost."