By Keith Coffman
DENVER (Reuters) - The parents of a teenager who stormed into his Colorado high school and opened fire with a shotgun, critically wounding a classmate, said on Monday they "cannot begin to understand" his actions and were praying for the victim.
Police say Karl Pierson, 18, was upset with a teacher when he walked into Arapaho High School in the Denver suburb of Centennial on Friday and shot Claire Davis at point-blank range before taking his own life in a classroom.
Davis, 17, is in a coma and was listed in critical but stable condition, her family said in a statement issued through the hospital where she is being treated.
"We are shattered by the tragic events that took place on Friday at Arapahoe High School. Our thoughts and prayers are with Claire Davis and her family," Barbara and Mark Pierson said in a statement released through a family friend.
"They, and she, have suffered unimaginably, and we pray for her full recovery," the couple said. "We also pray for the entire Arapahoe High School community, as we know your lives are forever changed by this horrific event.
The Piersons said they loved their son dearly and were devastated by Friday's shooting, adding: "We cannot begin to understand why Karl did what he did. We ask for privacy during this unthinkably difficult time and hope that you will respect our need for time to grieve.
Earlier on Monday, the Arapahoe County Coroner's office said that an autopsy conducted on the body of Karl Pierson showed he had died of a shotgun blast to the head.
Pierson was armed with a pump-action shotgun, a machete and three Molotov cocktails when he 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 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 has 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.
(Writing by Keith Coffman and Dan Whitcomb; Editing by Cynthia Johnston and Cynthia Osterman)