Arapahoe High shooter was angry about debate team demotion

CENTENNIAL, Colo. — Several students who say they know the Arapahoe High School shooter say he was reserved and had signs of rage, but none of them saw signs that would lead them to believe he would carry out the shooting.

Sheriff Grayson Robinson identified the shooter as Karl Halverson Pierson, 18.

“He was sorta nerdy, but in an almost charming way,” said fellow student Frank Warnoff.

One students who didn’t give his name said he last saw the shooter Wednesday. “He got suspended for yelling at my teacher,” the teen said. “Last time I saw him in a rage. Then he left.”

Pierson was a member of the school’s Speech and Debate team, but had been kicked off by the teacher he allegedly targeted, Warnoff said.

“Apparently that was enough to set him off,” he said.

Other students described Pierson as bright and conservative in his views on gun rights.

Authorities searched his Highlands Ranch home Friday night.