An indepth investigation into a school shooting outside Denver, CO last year has come to a close, with new details from the report expected to be released on Friday, ABC News reported.
The shooting occurred at Arapahoe High School on Dec. 13 when student Karl Pierson fatally shot a classmate before turning the gun on himself.
According to police, Pierson had a grudge against his debate coach and was planning to harm him when he arrived at school packing a machete, homemade bombs, a shotgun and 125 rounds of ammunition. Classmate Claire Davis, 17, was killed before Pierson committed suicide in the school library. The debate coach was not harmed during the shooting.
Pierson intended to have more victims that day, and even went so far as to write numbers and letters that went along with the library and four other classrooms on his arm before he arrived at school.
Littleton Public Schools, where the shooting occurred, boasted new guidelines for identifying severe threats to safety after the 1999 shooting at Columbine High School. In that case, both gunmen also committed suicide after killing 13 students, according to the Washington Times.
Just months before the Arapahoe shooting in September 2013, school administrators deemed Pierson to not be a high risk even after levied a death threat against the debate coach after he was demoted on the team. He was back in the classroom less than a week after making the threat, and according to disciplinary records, had no remorse for the things he said.
Pierson was sent home just two days before the shooting for pounding on a locked classroom door and yelling disturbing things while students were in class, according to school documents.
School administrator reportedly took no action after two crossing guards caught Pierson researching guns on his school computer months before the shooting, according to Christina Erbacher - Kolk, one of the school security workers that witnessed Pierson.
