The family of the 17-year-old Colorado girl fatally shot by another student at their school last month say they have forgiven the gunman. "My wife and I forgive Karl Pierson for what he did," Michael Davis said Wednesday night during a memorial for his daughter, Claire. "He didn't know what he was doing." Pierson, 18, shot Davis in the head before killing himself Dec. 13 at Arapahoe County High School in the Denver suburb of Centennial, sheriff’s investigators said. Officials believe Pierson's rampage was triggered by his losing his spot on the school's debate team. He stormed into the school armed with 125 rounds of ammunition, a machete and three Molotov cocktails, first firing a shotgun down a hallway. He then shot Claire point-blank while she sat nearby. Claire, who died eight days after the attack, was an innocent victim, officials said. She was remembered Wednesday as a popular student who loved horses and equestrian sports.