He called himself a “psychopath” in his secret diary and vowed revenge for slights dating back to elementary school before the Arapahoe High School shooter killed another student and himself last year, according to a sheriff’s report released Friday.
Law enforcement and school officials said that 18-year-old Karl Pierson, furious over being demoted Sept. 3 as a debate team captain, had become a discipline problem at school and threatened the debate coach, Tracy Murphy, before the deadly Dec. 13 rampage.
n his diary, Pierson also cited “elementary school teasing” and described himself as a “psychopath with a superiority complex” who wanted to commit “mass murder and be in a place of power where I and I alone are judge, jury and executioner.”
But two psychiatric evaluations conducted during the fall semester — a threat assessment by a school psychologist and a mental health evaluation done by therapists at a private behavioral clinic — determined he was a low-level threat, according to the 37-page report summary.
Arapahoe County District Attorney George Brauchler said at a Friday press conference that the gunman acted alone and that there were no plans to pursue charges against those who had evaluated him.