Updated Dec. 15, 2013, 10:07 a.m.
The student who opened fire at a Colorado school Friday and wounded another student intended to harm more people before killing himself, police said.
Karl Halverson Pierson was armed with a shotgun he purchased legally, a machete, three explosive devices and extra ammunition when he entered Arapahoe High School, Arapahoe County Sheriff Grayson Robinson said, according to the Associated Press. He fired six shots off a pump-action gun, directly hitting 17-year-old Claire Esther Davis before turning the gun on himself, all just 80 seconds after he arrived at the school.
“His intent was evil,” Robinson said. “And his evil intent was to harm multiple individuals.”
Pierson, a member of the school’s debate team, was possibly seeking retribution against the school’s debate coach, who was also the librarian. He was disciplined in September by his target, though the reason remains under investigation. Pierson also threatened the debate coach in September.
“[Pierson] was very outspoken — always involved with class discussion,” a fellow student told NBC News. “So it was kind of odd to see that he was the one who did this.”
“He had very strong beliefs about gun laws and stuff. I also heard he was bullied a lot,” another student told The Denver Post.
On Friday, when the shooting began, students quickly alerted the librarian, who made a “wise tactical decision” to leave the building to lure the shooter away from other students, Robinson said.
The shotgun Pierson carried was purchased legally from a local store on Dec. 6. The ammunition was purchased on the day of the shooting.
Davis, likely caught in the crossfire and not a specific target, has severe head trauma remains in critical condition.
Arapahoe County is where the Aurora movie theater shooting took place last year, when a gunman opened fire during a late-night movie premiere and killed 12 people. Arapahoe County High School is only about eight miles west of Columbine High School, the site of one of the worst school shootings in U.S. history in 1999. The latest shooting took place just one day before Saturday’s one-year anniversary of the mass shooting at a Connecticut elementary school.