Cops say Karl Pierson was “really, really angry” at his debate coach, keying the shooting spree that injured three Friday at Arapahoe High School in Colorado.
Students told the Los Angeles Times that Pierson, who killed himself to end the horror, had a disagreement with his coach.
It began when Pierson and his coach argued over changes the teenager wanted to make to the debate team.
The disagreement ended with Pierson being kicked off the team last September after he threatened the teacher.
As late as Monday a team co-captain asked Pierson to come back to the team. But he said no and told the classmate he still hated the teacher and then added “apparently you get suspended for threatening to kill a teacher.”
Students said they believe Pierson was even more upset after the team won first place in a tournament.
Reports say Pierson yelled the coach’s name as he entered the school. He found the man and fired a shot at him but missed.
The coach ran out of the school and was not injured.
NBC reports the sheriff believes “that may have been “the most important tactical decision that could have been made.”
It’s thought that since Pierson had a singular focus, fewer people were hurt.
However, the 15-year-old girl who was shot is still in critical condition and cops say “there’s no reason to believe she was a target.”
Students describe Pierson as “slightly geeky,” but smart, with a keen interest in politics and guns.
They also say he was frequently bullied.
Another added “only those that could cope with his personality became close with him.”
Another pointed out Pierson seemed very different when his parents were recently divorced.