Colorado Shooting

Investigators look over evidence on ground outside the back door of the Century 16 movie theater east of the Aurora Mall in Aurora, Colo. on Friday, July 20, 2012. A gunman in a gas mask barged into a crowded Denver-area theater during a midnight showing of the Batman movie on Friday, hurled a gas canister and then opened fire in one of the deadliest mass shootings in recent U.S. history. (AP Photo/David Zalubowski)