Holmes, 24, received deliveries over four months to his home and school, authorities said yesterday. University spokeswoman Jacque Montgomery said on 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 on Saturday.
Investigators spent hours yesterday removing explosive materials from inside Holmes' apartment a day after police said he opened fire and set off gas canisters in a theatre minutes into a premiere of the new Batman film "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.
Inside the apartment, FBI Special agent James Yacone said bomb technicians neutralised 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.
By late yesterday afternoon, all hazards had been removed from 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 Alcohol, Tobacco, Firearms agent 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.
Aurora: The University of Colorado said it's investigating whether mass 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.
First Published: Monday, July 23, 2012, 13:49