The 18-year-old Colorado gunman who stormed his suburban Denver high school and shot and critically wounded a classmate last week before committing suicide died of a shotgun blast to the head, the county coroner said on Monday.
An autopsy conducted on the body of Karl Halverson Pierson revealed he died of "a severe head injury," the Arapahoe County Coroner's Office said in a statement that classified the death as a suicide.
The 17-year-old victim of the shooting spree, Claire Davis, is in a coma and is listed in critical but stable condition, her family said in a statement issued through the hospital where she is being treated.
Armed with a pump-action shotgun, a machete and three Molotov cocktails, Pierson entered Arapahoe High School in Centennial on Friday, firing the weapon and igniting one of the explosive devices.
The rampage took place just 8 miles (13 km) from the scene of one of the deadliest school massacres in U.S. history, Columbine High School, where two students gunned down 13 classmates and staff before killing themselves in 1999.
Arapahoe County Sheriff Grayson Robinson said Pierson had been upset with a teacher identified as the school's debate coach and librarian, Tracy Murphy, who had disciplined Pierson, a member of the debate team, earlier in the school year.
Pierson shot Davis in the face at point-blank range outside the library, then shot himself as an armed deputy cornered him in the library, Robinson said.
Investigators concluded their processing of the crime scene, and turned the facility back to the school district on Monday, the sheriff's office said. The Littleton School District said classes will not resume at the 2,000-student school until January.
© 2015 Thomson/Reuters. All rights reserved.