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Yellow markers sit next to evidence, including a gas mask, as police investigate the scene outside 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)

Colorado suspect's booby-trapped home

In Aurora, investigators spent hours July 21 removing explosive

materials from inside Holmes' apartment, rigged with jars of liquids, explosives and chemicals that were booby trapped to kill "whoever entered it," a day after police said he

opened fire and set off gas canisters in a theater minutes into a

premiere of the "The Dark Knight Rises." The massacre left 12 people dead and 58 injured.