The suspect, who entered Arapahoe High School carrying a shotgun, was found dead in the school. Watch live coverage »
iHeartRadio's 'Jingle Ball' live at Madison Square Garden
Watch the concert starring Miley Cyrus, Selena Gomez, Robin Thicke, and more starting tonight at 8 p.m. ET/ 5 p.m. PT, live on Yahoo Screen.