Pierson entered Colorado high school with shotgun, machete, 125 rounds DENVER, Dec. 18 (UPI) -- The Colorado student who shot a teenage girl was heavily armed when he entered Arapahoe County High School looking for his debate coach, the local sheriff says. Arapahoe County Sheriff Grayson Robinson said Karl Pierson had written reminders on his arm of five classrooms and the library he planned to attack, the Denver Post reported Wednesday. Pierson brought with him a 12-gauge pump shotgun, three Molotov cocktails and a machete, Robinson said. He also had 125 rounds of ammunition on two bandoleers. On the inside of his foreman, Robinson said the 18-year-old had written in Latin: "Alea iacta est" - "The die has been cast." "The shooter was intent on causing the maximum amount of harm," the sheriff said. Pierson fired five times, with one of his shells hitting Claire Davis, 17, in the head last Friday. She remains in a coma in critical condition. The shooter lit a firebomb in the library that set three bookshelves on fire. He then shot himself in the head.