ARAPAHOE COUNTY, Colo. -- A stunned community had a prayer vigil Sunday in support of Claire Davis, 17, who was clinging to life after being shot in the head Friday by a fellow student at Arapahoe High School.
The horse lover, babysitter and "great student" remained in critical condition at Littleton Adventist Hospital. Her school cancelled Monday classes.
Colorado's governor asked the nation Sunday for prayers for Claire.
Gov. John Hickenlooper credited security procedures adopted after the 1999 massacre at nearby Columbine High School for helping put a quick end to the shooting.
"We all have to keep Claire in our thoughts and prayers," he told CBS' Face the Nation.
Claire's parents "are remarkable people. I feel so directly their suffering. ... They raised this beautiful young woman who had her whole life ahead of her," Hickenlooper told the Associated Press.
August Clary, a classmate and friend, said horsemanship is a big part of Claire's life. She spends long hours training her horse, Graphite, August said.
"A very sweet girl. She's really smart, really bright," said August, who has known Claire since freshman year. He had government class with her Friday morning.
"She wouldn't hurt a fly. She's just a really great girl, and we hope she's gonna be OK."
Pierson was "a funny kid," August said. "He's smart. He's in the Eagle Scouts, a very intelligent kid. Did not like being wrong. If you're arguing with him ... that's a feat if you win an argument against him."
Hundreds of students, parents and community members filled a local park Saturday night for a candlelight ceremony, expressing shock and pain at the tragedy that unfolded at the Centennial school.
"It didn't feel real until you see everybody" at the vigil, said Summer Skrzypek. "She was a good friend and was always there if you needed her."
Students sang the school fight song and reminded each other that "Warriors" stick together. They shouted out words of encouragement, held a moment of silence and prayed.
Claire's neighbors were trying to process news of the shooting. Walter Bushnell toldThe Denver Post that Claire's grandmother had told him Claire was the victim.
"I just thought, 'Oh, my God, it's her' — it's just tragic," Bushnell said. "I'm just in shock."
Matt DeNero, who lives across the street from the Davis home, told the Post she was outgoing, a good athlete and great student.
"We've watched her grow up since she was 2," DeNero said.
On Saturday, Arapahoe County Sheriff Grayson Robinson called Davis "a young woman of principle. She is a young woman of purpose.... She was an innocent victim of an evil act of violence."
Robinson said Karl Pierson, 18, who died of a self-inflicted gunshot, entered the school armed with a shotgun he bought legally, rounds of ammunition strapped across his body, a machete and a backpack with three Molotov cocktails.
Pierson, in less than two minutes, fired five shots and ignited one of the Molotov cocktails before running to the back of the school library and killing himself, Robinson said. Robinson credited the quick response of a sheriff's deputy assigned to the school with stopping a mass murder.
"The shooter knew the deputy was in the area," Robinson said at a news briefing. "We believe that the response ... was absolutely critical to the fact that we did not have additional injury or deaths."
Tracy Murphy, a librarian and debate team coach, was believed to have been the gunman's target. Pierson was unable to find Murphy, who coached Pierson and had disciplined him in September. Robinson said Claire's shooting appeared to be random.
The Davis family issued a statement Saturday saying Claire "has severe head trauma as a result of a gunshot. She needs your continued prayers."
The statement thanked family, friends, the community and the equestrian community for their outpouring of love and support, as well as the school for their continued support of the students and teachers."
The family also thanked first responders and medical personnel for "saving our daughter's life."
Meagan Fitzgerald and Laurie Cipriano report for KUSA-TV in Denver. Contributing: Carolyn Pesce, the Associated Press.