DENVER—Administrators at a suburban Denver high school dismissed increasingly obvious warning signs that a troubled student was a threat before he killed a classmate and himself two years ago, a report released Monday shows.
Arapahoe High School staff poorly gauged the rising threat Karl Pierson, 18, posed months before he stormed the school with a shotgun, a machete and homemade bombs and shot Claire Davis, 17, in December 2013, according to the 141-page report by the University of Colorado’s Center for the Study and Prevention of Violence.
The shooting might have been prevented if school staff had kept detailed and more widely accessible records documenting concerns over Pierson, the report says. Administrators also failed to thoroughly investigate threats he made.
