Bailey, Colo. ? A gunman took six girls hostage at the high school in this mountain town Wednesday, using them as human shields for hours before he shot and fatally wounded a girl and then killed himself as a SWAT team moved in, authorities said.

The confrontation at Platte Canyon High School unfolded just a short drive away from Columbine, the site of one of the nation’s deadliest school shootings. The gunman, believed to be between 30 and 50 years old, was cornered with the girls in a second-floor classroom, and he released four of them, one by one.

Park County Sheriff Fred Wegener said authorities decided to enter the school to save the two remaining hostages after the man cut off negotiations and set a deadline. He said authorities used explosives as they entered the classroom, only to have the suspect fire at officers, shoot one of the girls and then himself.

The man was not immediately identified – one official declared him a virtual John Doe – and the sheriff was at a loss to explain a motive.

“I don’t know why he wanted to do this,” Wegener said, his voice breaking.

Platte River sophomores and friends Taylor Fraser, 15, left, and Sophie Sasser, 15, hug after being reunited Wednesday at the Deer Creek Elementary School near Bailey, Colo. A gunman took six girls hostage at the high school Wednesday, holding authorities at bay for hours before fatally shooting one of the girls and killing himself as a SWAT team moved in.

The wounded girl – identified by acquaintances and a co-worker as 16-year-old Emily Keyes – was taken to a Denver hospital in critical condition, but was declared dead, a hospital spokeswoman said.

The last hostage was unharmed and spoke with authorities. School was canceled for the rest of the week.

“We are a community in mourning,” schools Supt. Jim Walpole said. “Our thoughts, our prayers are with our students, staff and their families. Especially the family of the student we lost.”

After the suspect entered the building, hundreds of students were evacuated. The sight of students fleeing the high school in long lines, and of frantic parents scrambling to find their children, evoked memories of the 1999 attack on Columbine High School, where two students killed 13 people before committing suicide.

Students said the bearded suspect wore a dark blue hooded sweat shirt and a camouflage backpack. The sheriff said the man claimed to have a bomb in the backpack and threatened to set it off. The man was also toting a handgun.

Students described a chaotic scene inside after the intercom announced “code white” and everyone was told to stay in their classrooms.