(AP) AURORA, Colo. - The University of Colorado said it's investigating whether shooting suspect James Holmes used his position as a graduate student to order materials in the potentially deadly booby traps that police said they found in his apartment.
Holmes, 24, received deliveries over four months to his home and school, authorities said Saturday. University spokeswoman Jacque Montgomery said Sunday the school is looking into those packages received at the school.
That detail emerged with other information on the suspect described as a budding scientist, brimming with potential, who pursued a graduate program even as he planned the attack with "calculation and deliberation," police said Saturday.
Investigators spent hours Saturday removing explosive materials from inside Holmes' apartment 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.
His apartment was rigged with jars of liquids, explosives and chemicals that were booby trapped to kill "whoever entered it," Aurora Police Chief Dan Oates said, noting it would have likely been one of his officers.
"What we're seeing here is evidence of some calculation and deliberation," Oates added.
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Inside the apartment, FBI Special agent James Yacone said bomb technicians neutralized what he called a "hypergolic mixture" and an improvised explosive device containing an unknown substance. There also were multiple containers of accelerants.
"It was an extremely dangerous environment," Yacone said at a news conference, noting that anyone who walked in would have sustained "significant injuries" or been killed.
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By late Saturday afternoon, all hazards had been removed from the Holmes' apartment and residents in surrounding buildings were allowed to return home, police said.
The exception was Holmes' apartment building, where authorities were still collecting evidence. Inside the apartment, authorities covered the windows with black plastic to prevent onlookers from seeing in. Before they did, a man in an ATF T-shirt could be seen measuring a poster on a closet that advertised a DVD called "Soldiers of Misfortune." The poster showed several figures in various positions playing paintball, some wearing masks.
About 8 p.m. Saturday, police left the apartment building carrying a laptop computer and a hard drive.
Explosive material removed from suspect's apt.
While authorities continued to refuse to discuss a possible motive for one of the deadliest mass shootings in recent U.S. history, details about Holmes' background as a student and would-be scientist trickled out.
Holmes had recently withdrawn from the competitive graduate program in neuroscience at the University of Colorado Denver, where he was one of six students at the school to get National Institutes of Health grant money. He recently took an intense three-part, oral exam that marks the end of the first year of the four-year program there, but university officials would not say if he passed, citing privacy concerns. The university said Holmes gave no reason for his withdrawal, a decision he made in June.
