Authorities and classmates were left wondering what drove a 15-year-old to open fire at his high school, killing an assistant principal and seriously wounding the principal and another administrator.
No students were hurt in Tuesday's shooting. The 1,400-student school about 35 miles northwest of Knoxville was closed for the rest of the week, officials said.
Ken Bartley Jr. was taken to a juvenile detention facility, Sheriff Ron McClellan said. Bartley's family declined comment.
"He has been in trouble before, but I just wouldn't expect something like this out of him," said classmate Courtney Ward, 17. "He is a big jokester. He is rowdy. But I just couldn't see him doing this."
Authorities didn't know whether Bartley would be charged as an adult. They said he was grazed in the hand by a bullet fired from his own .22-caliber handgun when he was subdued.
"I don't know what he was thinking or what his motives were," McClellan said. "Investigators are piecing together ... what exactly transpired."
Assistant Principal Ken Bruce was shot in the chest and died at a LaFollette hospital, authorities said.
Principal Gary Seale was shot in the lower abdomen and Assistant Principal Jim Pierce was hit in the chest. They were in serious condition in intensive care at University of Tennessee Medical Center in Knoxville, spokeswoman Lisa McNeal said.
The administrators and a teacher helped wrestle the gun away from Bartley, deputies said.
After he was shot, the principal went to the school intercom and ordered a lockdown, students said. Officials said the quick action helped contain the rampage.
"This situation could have gotten much worse," said Mark Wells, vice chairman of the Campbell County Board of Education. "It did not because our staff followed the (emergency) plan in place."
Parents rushed to the school to collect their children, causing a massive traffic jam when police closed the campus.
"It is scary, it is terrifying," said Darren Davidson, waiting for his son, Justin, to come through the school's gates. His wife, Kizzie Davidson, added: "I thought I would have a heart attack before I got here."
Both Seale and Pierce have been educators more than 30 years, said former assistant principal Clifford Kohlmeyer. Bruce had been a lieutenant colonel in the Army and came back to teaching about eight years ago, Kohlmeyer said.
Tuesday's shooting marked the second time this year that a school employee was fatally shot.
Stewart County school bus driver Joyce Gregory, 47, was killed as she stopped to pick up a student on her route on March 1. Jason Clinard, 15, is charged with her murder and will be tried as an adult.
In August, a boy was accidentally shot in the leg in a middle school restroom in Jefferson County. The investigation led to charges against two students accused in a plot to kill a teacher at Maury Middle School.