Associated Press

LITTLETON, Colo. — A teenager who fatally shot another student at his suburban Denver high school last year had been deemed “not a high-level of threat” after shouting a death threat against his debate coach three months earlier, according to documents obtained by The Associated Press.

The disciplinary records show that Karl Pierson, 18, was allowed to return to class in September, less than a week after he was demoted from captain of the debate team and said he would kill the coach, who was a school librarian. The documents say Pierson showed no remorse for making the threat.

Authorities have said Pierson was targeting the debate coach when he entered Arapahoe High School on Dec. 13 with a shotgun, a machete and homemade bombs. Pierson killed a 17-year-old girl before taking his own life in the school library as security officers closed in. The coach, whose name has not been publicly released, escaped unharmed.

The documents offer the first glimpse into the response to the threat Pierson made Sept. 3. Authorities and school officials have acknowledged that he threatened the debate coach but have never explained how that threat was handled, even after other students’ parents demanded answers.

The documents also show that just two days before the shooting, school officials sent Pierson home early after he pounded on a locked classroom door so hard that teachers in other classrooms could hear him.

The information in the documents, which were submitted into Pierson’s student record by then-Assistant Principal Kevin Kolasa, was verified by two people familiar with the investigation who spoke on condition of anonymity because they were not authorized to talk about it.

Kolasa, now the assistant principal of a middle school in the same district, did not return calls seeking comment and was not home when a reporter visited.

Littleton Public Schools Superintendent Scott Murphy refused to comment on the documents last week, saying it is district policy not to comment on individual student disciplinary cases.