18-year-old Karl Pierson, the Colorado student who opened fire at Arapahoe High School last week apparently planned to attack at least five different areas, investigators said on Tuesday, as reported by The Huffington Post.
Letters and numbers corresponding to the "locations of the high school library and four adjacent classrooms were written in indelible marker on [his] arm and investigators believed he planned to target those spots," Arapahoe County Sheriff Grayson Robinson said in a statement. Also written on Pierson's arm was the Latin phrase "Alea iacta est," which translates to "The die has been cast," according to news reports.
Investigators were trying "to determine if the occupants of those rooms may have been personally targeted by Pierson," The Huffington Post also reported.
The county sheriff previously said that "investigators believed a librarian who headed the school's speech and debate team was Pierson's intended target Friday, but he also planned to harm many others," according to news reports. While the librarian escaped, Pierson critically wounded 17-year-old senior, Claire Davis, "whom he encountered soon after entering the school armed with a 12-gauge pump-action shotgun, a machete and three Molotov cocktails," according to news reports.
Pierson ultimately killed himself in the library "with his sixth and final shot 80 seconds after entering the school, as a school resource officer was closing in," The Huffington Post also reported.
Robinson also gave more details Tuesday about the amount and type of ammunition Pierson carried - more than 125 rounds of steel-shot, buckshot and slug ammunition.
