Aurora, Colo. (AP) - The shooting suspect accused in a deadly rampage inside a Colorado theater planned the attack with "calculation and deliberation," police said Saturday, receiving deliveries by mail that authorities believe armed him for battle and were used to rig his apartment with dozens of bombs.
In Aurora, investigators spent hours Saturday removing explosive materials from inside Holmes' suburban Denver apartment a day after police said he opened fire and set off gas canisters in a theater minutes into a premiere of the Batman film "The Dark Knight Rises."
Authorities found more than 30 improvised explosive devices in Holmes' apartment. Aurora's Police Chief says Holmes' intent with these materials was clear.
"Make no mistake. This apartment was designed, I say, based on everything I've seen, to kill whoever entered it," said Chief Dan Oates. "Who was most likely to enter that location after he planned and executed this horrific crime? It was gonna be a police officer."
Holmes received several mail deliveries over four months to his home and school and bought thousands rounds of ammunition on the Internet.
"He had a high volume of deliveries," Oates said. "We think this explains how he got his hands on the magazine, ammunition," he said, as well as the rigged explosives in his apartment.
"What we're seeing here is evidence of some calculation and deliberation," Oates added.
All residents living nearby can now return to their homes except for those in Holmes' apartment building, where FBI agents are still collecting evidence.
Oates said he's outraged over the shooting that killed 12 and injured 58 others.
"If you think we're angry, we're sure as hell are angry about what has happened to our city, what has happened to these wonderful people who live here and also what he threatened to do to one of our police officers," Oates said at a press conference Saturday.
Oates added that police officers are not immune to the trauma on an event like this.
"Our cops went through a lot," he said. "They rushed people out of that theater into police cars. ... One of our highest priorities is dealing with our own officers and how they cope with this event."
© 2012 The Associated Press. All Rights Reserved.