A Colorado teenager shot by a classmate at Arapahoe High School earlier this month has died. Claire Davis, who was 17, had been in critical condition since December 13, when she was shot by Karl Pierson, a fellow student, who then shot himself. Authorities believe Pierson randomly targeted Davis while seeking a librarian who had disciplined him. Meanwhile in Chicago, Illinois, at least three people were killed and 15 wounded in a series of shootings this weekend, including one that killed an 18-year-old.