CENTENNIAL, Colo. The teen gunman who shot himself dead after critically wounding a fellow student at their suburban Denver high school apparently acted in retaliation for discipline leveled against him by the school's debate club coach, the county sheriff said on Saturday.
Sheriff Grayson Robinson also said that 18-year-old Karl Pierson legally purchased the shotgun and ammunition he used in Friday's rampage at Arapahoe High School. The sheriff said the attack lasted less than a minute and a half.
The faculty member who was believed to be Pierson's intended target fled the school and was unharmed in the rampage.
(Reporting by Keith Coffman; Writing by Steve Gorman; Editing by David Brunnstrom)