Two days after 12 people, including a six-year-old girl, were killed and 58 others wounded during the premiere of new Batman movie 'The Dark Knight Rises' at an Aurora theatre in Denver, Colorado, US President Barack Obama was set to visit the injured and families who lost their loved ones.
Last night, investigators carried out "controlled detonation" in Holmes' booby-trapped one-bedroom apartment after which they entered the house in a bid to find out clues to the motive behind the deadly attack.
At least 30 improvised explosive devices were found when police entered the Denver apartment of Holmes, who was arrested after the shooting.
Police said Holmes may have been planning the attack for a long time as he received a high volume of deliveries over the past four months to both his home and work addresses.
"What we're seeing here is evidence of, I think, some calculation and deliberation," Aurora Police Chief Daniel Oates said. "We have the evidence of a deliberative process to commit this assault, and we have the evidence of a deliberative process in his mind to attack whoever opened the door of his apartment."
"Make no mistake," Oates said, "this apartment was designed to kill whoever entered it."
Police had evacuated hundreds of residents from five apartment buildings, including the one where Holmes lived, after he told them he had rigged his apartment with explosives. (More)