Bomb squad disarms booby trap with controlled explosion

US police began the intricate process of disarming booby traps in the apartment of the suspect behind the Colorado cinema shootings, hoping to find clues to the motive for the rampage without causing an explosion that could destroy key evidence.

A controlled explosion by a bomb squad appeared to have made it safe for police to enter the booby-trapped apartment of the man suspected in Friday's mass shooting at a Denver-area movie theater, police said.

Police were undertaking the delicate task of disabling what they described as sophisticated explosives at the Aurora, Colorado, apartment of suspect James Holmes, who officials believe booby trapped his home before killing 12 people and injuring more than 50 others at the cinema early on Friday.

A small amount of smoke is seen at a window of Holmes' apartment in Aurora
A small amount of smoke is seen at a window of Holmes' apartment in Aurora Credit: Reuters

The bomb squad used a robot to place a tube - known as a "water shot" - near an explosive device in the apartment. The water shot was then detonated to disable the explosive.

Photos of the apartment, taken by a camera raised up to the third-floor window, showed jars of ammunition on the floor and "things that look like mortar rounds," Aurora Police Chief Dan Oates said. There were also bottles filled with an unknown liquid as well as what appeared to be trip wires laid out across the apartment, he said.

Aurora Police spokeswoman Sergeant Cassidee Carlson said the device had clearly been "set up to kill."

"We have been successful in disabling a second triggering device," she said. "Although not certain, we are hopeful we have eliminated the remaining major threats. We will not know this until we enter the apartment."

Police on a roof top across from Holmes' apartment in Colorado
Police on a roof top across from Holmes' apartment in Colorado Credit: Reuters

Police said the suspect received a high volume of deliveries at work and home over the past four month - parcels they believe contained ammunition and possibly bomb-making materials.

Aurora Police Chief Dan Oates revealed the shipments as local and federal authorities worked to make safe suspect James Holmes' apartment, which was found to be booby-trapped with sophisticated explosives following the massacre at a multiplex theater several miles away.

Oates said residents of nearby buildings who were evacuated would likely be allowed to return home on Saturday night.

"We've become aware that the suspect over the last four months received a high volume of deliveries to both his work and home addresses," Oates said at a press conference.

"This begins to explain how he got his hands on all the magazines and ammunition, " Oates said. "We also think it begins to explain some of the materials he had in his apartment."

Officers put a container filled with blue liquid to use in the explosion
Officers put a container filled with blue liquid to use in the explosion Credit: Reuters

"There still remains all kinds of hazards inside the apartment," Carlson said. "We will remain here for hours to collect evidence and mitigate those hazards."

Police evacuated five nearby buildings and created a perimeter of several blocks around Holmes' apartment, the top-floor unit of a three-story red brick building in a run-down section of Aurora.

The shooting occurred as hundreds of people watched sold-out midnight screenings of "The Dark Knight Rises" at a mall in Aurora.

The gunman - armed with an assault rifle, a shotgun and a pistol, and wearing a full suit of tactical body armor, a helmet and a gas mask - set off two smoke bombs before opening fire in the dark cinema.

Officers who arrived on scene within 90 seconds of the first emergency calls quickly took Holmes, 24, into custody in a parking lot behind the cinema, where he surrendered without a fight, Oates said.

Holmes, a graduate student who authorities said had his hair dyed red and called himself "the Joker" in a reference to Batman's comic-book nemesis, was due to make an initial court appearance on Monday.

Holmes lived on the third floor of the Aurora apartment complex that had been evacuated.

The 24-year-old is in police custody at the Arapahoe County jail and is expected to make his first court appearance on Monday morning.