BAILEY, Colo. -- Authorities said the suspected hostage-taker at a Colorado high school had sexually assaulted some of the girls he was holding Wednesday afternoon.

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Park County Sheriff Fred Wegener said that became clear both during negotiations with the man, as well as through observations by a SWAT team.

Wegener was joined by other officials in a news conference just outside the school on Thursday morning.

"I've gone from upset to angry," said Wegener as he began the news conference.

The suspect is now identified as Duane R. Morrison, 54, a man who was living out of his car, but had a Denver address. Authorities said Morrison had no known connections to Bailey, Colo., on the outskirts of Denver.

According to the sheriff, Morrison was threatening that something would happen at 4 p.m. Wednesday afternoon. Based on that -- and the assaults on the girls -- Wegener said he decided to try to save the two girls who were still being held.

"He did traumatize and assault our children. This was information was sent to me by the SWAT team. This is why I made the decision I did. We had to go try and save them," Wegener said.

A SWAT team was sent in, but Wegener said as they burst through the door, Morrison opened fire on them, then fatally shot one of the girls before killing himself.

He told reporters that Morrison was armed with two weapons: a semiautomatic pistol and a revolver.

One of six female students at Platte Canyon High School who were held hostage died after she was shot in the head by the gunman as the SWAT team moved in to end the four-hour standoff.

Emily Keyes, a 16-year-old junior, died at St. Anthony hospital in Denver after she was airlifted from the school.

Investigators still don't know Morrison's motive. They said he had a minor criminal record.

Community Wonders Why

The day after the standoff, a Colorado community is reeling from the reality of what happened.

Many were asking questions: "Why here?" "Why us?" "How could it happen?"

The bucolic town of Bailey, Colo., about 40 miles southwest Denver and 30 miles from Columbine High School, where the worst school massacre in U.S. history occurred, is the scene of the latest school shooting.

The gunman was dead at the scene and his body remained inside the school until early Thursday. It appeared that he shot himself, but SWAT team members also shot at him at the same time.

"There are no known connections in this area, but the investigation is still ongoing there," Wegener said.

Wegener said the motive "still remains a mystery" and that Morrison had a "minor" criminal history.

He said Morrison's vehicle was located and searched but he didn't say what was found.

"This is an ongoing investigation," he said. He asked anyone who had information on Morrison to call a tip line at 303-816-5947.

On Wednesday, Wegener was emotional as he talked about the shooting.

"I've been here 36 years, so I do know the family," said Wegener, whose son was also inside Platte Canyon High School at the time. "The community's probably going to be in shock right now, rightfully so."

Wegener's son is a junior at the high school. His daughter graduated last spring. The sheriff graduated from the school in 1981.

How It Started

The hostage situation began when the gunman walked into the school at about 11:40 a.m., said he had a bomb in a backpack and fired several shots inside a classroom. Six female students in a second-floor honors English classroom were taken as hostages as the school went into "code white" and Park County deputies rushed to the scene, evacuating everyone from the building.

Code white is the school code known to teachers that alerts them a gunman is in the school.

Jefferson County SWAT team and bomb team was called in to aid the rural Park County Sheriff's Office. Officers moved into the school and confined the gunman to a single classroom -- a lesson learned from Columbine. Deputies established verbal contact with him minutes into the incident through the door of the classroom. The suspect initially talked to deputies but later spoke only through the hostages, authorities said.

The gunman released four students one by one, negotiating with authorities through them by telling the students he released to tell deputies of his demands.

"Most of the demands strictly were, they wanted us to back off," Wegener said.

The gunman shielded himself with the hostages -- making it hard for the SWAT teams -- and talked only through the teens, either directly -- by having them yell through the door -- or by cell phone.

These sporadic negotiations continued until four hours later, when he set a 4 p.m. deadline, broke off all communication, and kept two students with him, authorities said.

"It was then decided that a tactical solution needed to be done in an effort to save the two hostages that were in the room," Wegener said.

At about 3:30 p.m., the SWAT team deployed shock grenades to force their way in.

"Officers breached the classroom with explosives. Within seconds, the suspect shot at entering SWAT officers, then shot one of the two female hostages and then shot himself. During the gunfire, SWAT officers pulled an additional hostage from the room and she fled the building on foot," Wegener said.

The victim was airlifted to St. Anthony Central Hospital, but efforts to save her life were not successful. She was pronounced dead about an hour after arriving.

The other female hostage in the room was unharmed. She was being interviewed by detectives who are trying to piece together what happened during the last couple hours -- when there was only three of them in Class No. 206.

Students Spoke To Gunman Before Hostages Taken

Students said the bearded gunman was wearing a dark blue hooded sweatshirt and a camouflage backpack as he walked around the campus.

Jesse Kirby, a freshman at Platte Canyon High School, said he spoke to the gunman just moments before the hostage crisis.

"He didn't really look like a student, although he did because he was wearing all of our school stuff. But when he turned around and he looked at me, he had long gray hair sticking out of his hoodie. He was wearing his hood up, so it was really hard, and he said, 'Hey.' And I was like, 'Hi.' He asked me what class I was going to. I was like, 'I'm going to English I,' and he said, 'You're lucky,' " said Kirby. "And I was like, 'It's English!' And he was like, 'I loved English.' And I was like, 'I don't.' And there was an awkward silence and then I just went to my class. And then like five minutes later, we heard the big boom."

A female student said moments before, the gunman asked her to go with him to the English college prep class and she declined, saying she had to go to her own class.

Tom Grigg said his 16-year-old son, Cassidy, was in a classroom with 20 other students and their teacher, Mrs. Smith, when the man walked in, fired a gun and began telling some students to leave and others -- all girls -- to stay.

"We were about 35 to 40 minutes into the class when his guy that no one recognized came into the classroom and shot his gun into the ground," Cassidy Grigg told Good Morning America on Thursday. "He went one by one and told us we could leave or told us we had to stay."

Grigg said he kept the females but told the male students to leave.

"He hand-picked the ones he wanted to get out," said Grigg.

Tom Grigg said his son told the gunman he didn't want to leave his friends.

"The guy flipped him around and put the gun in his face and said, 'It would be in your best interest to leave,"' Grigg said.

The gunman was armed with a 9-mm handgun. His claim of having a bomb in his backpack turned out to be a lie.

The gunman has not been publicly identified, although he appeared to be familiar with the school. Authorities are hoping that once they clear the school parking lot and students and staff go to retrieve their vehicles, the gunman's car would still be in the parking lot.

"Until this point, we would consider the gunman to be nothing more than a John Doe, until we take care of some initial things and identify some initial things," said Steve Johnson with the Colorado Bureau of Investigation, who is now leading the criminal investigation.

Authorities say they still don't know the gunman's motive for invading the school and taking specifically female students hostage.

"We have almost no information on this suspect. We don't know who is, we don't know what he wants ... We'd like to know what he wants," Kelley had said, earlier in the day.

It's not clear what the man's 4 o'clock deadline pertained to. The gunman said that "something will happen" at 4 p.m., according to Wegener.

No School Thursday, Friday As Community Mourns

Friends rushed to St. Anthony Hospital to comfort each other after learning about what happened to Keyes.

"She's in speech. She's a really good girl. She's always been very nice to people. She's kind of quiet but she would never do anything to anybody to deserve this," said the victim's friend, Jessica Leedom.

Bailey, a bedroom community of about 5,500 people, will be reeling from the tragedy for for some time.

"We are such a close community. Forty-three of the students in my kid's class, in 11th grade alone, 43 have been together since first grade," said parent Shelly Jakubiak.

"We are a community in mourning. Our hearts and prayers are with our students, staff and their families, especially the family of the student we lost," said Platte Canyon District Superintendent Jim Walpole.

Walpole said that Platte Canyon High School and Fitsimmons will be closed the rest of the week.

"The middle and high school buildings are sealed as a crime scene and will be for an undetermined amount of time," Walpole said.

He said Deer Creek Elementary will hold class as planned but that crisis counselors and victims advocates will be available at Deer Creek and also at Platte Canyon Community Church in Bailey for all students, staff and family members.

He said school officials will announce later this week when school will reopen during the week of Oct. 2.

The two schools that are affected are about four miles west of Bailey, which is in Park County. The two schools have an enrollment of about 770 students, with 460 in the high school.

Drill Turned Out To Be Real

Park county authorities first responded to the scene but then asked for help from the Jefferson County Sheriff's SWAT team and bomb squad. The FBI, the ATF, and the CSP all assisted the Park County and Jefferson County Sheriff's Office in the case.

Park County sheriff's deputies, many of whom have family in the school district, responded with their "active-shooter" plan -- an emergency drill prompted by the Columbine shootings. But first responders and the students learned quickly that this wasn't practice, and that the real deal could be frightening.

"I'll be honest, I was scared to death. Nobody wants anything like this to ever happen to their school. Certainly we trained for it, we've talked about it, and I was just praying that we do the right thing," Wegener said. His son is a student at the school.

"We were in there for about half an hour and the policeman came in and he said, 'Don't panic, the shooter's in the next room.' And then everyone, right then, started crying," said freshman Jackie Mace, who was several classrooms away. "Once we got out of the classroom, the policeman said, 'Hands on your head. And we went out there, screaming, thinking that the shooter was out there, so we went back into the classroom. I heard kids were against the chalkboard, he was putting guns against their heads, asking their names, and supposedly smelling them or telling them something. And I think that he shot the gun against the wall just to scare them."

"The Colorado Bureau of Investigation and all of their available resources will be used to conduct the criminal, ongoing investigation into this tragic event. We are in the very early stages of this criminal investigation. There is not a lot of information that can be released," said CBI's Steve Johnson. "We will be taking steps to assure that our investigation is thorough, prompt, and that we leave, obviously, no stone unturned. Our responsibility is to provide this community with the answers into the criminal episode that took place."

"Even though law enforcement agencies train for situations like this one, we never expect it will happen in our own back yard," Wegener said.

U.S. Highway 285, which runs in front of the school, was closed from Bailey to Shawnee. Emergency equipment was parked on the highway in front of the school and there was a steady stream of emergency equipment coming down the highway from the direction of Denver on Wednesday afternoon.

The high school football field, across the highway from the school complex, was used as a staging area for ambulances and emergency personnel. A Flight For Life chopper landed on the football field and was later used for Keyes.