AURORA, Colo. - Bomb experts detonated a second explosive device Saturday after disarming a trip wire attached to another bomb in the booby-trapped apartment of the suspected gunman who police say killed 12 and wounded 58 in a shooting rampage in a packed movie cineplex.
Police closed off several blocks around the building ahead of igniting the small bomb, yelling "fire in the hole!" three times before an explosion could be heard.
Aurora police Sgt. Cassidee Carlson had said investigators were closer to entering the apartment after authorities "defeated" the trip wire that was rigged to detonate when the front door was opened.
She said that "this is clearly set up to hurt somebody entering the apartment. It was set up to kill. This is serious stuff."
After disrupting the second device, authorities were deploying a robot to assess whether it was safe enough for bomb technicians to enter the apartment, a federal law enforcement official said.
The official, who is not authorized to comment publicly, said it was not clear when the unit could be determined safe for human entry.
"Everything is being dictated by level of safety," the official said. "There is no ticking clock."
The Associated Press, quoting a law enforcement official, reported that officers disarmed one explosive with a "water shot," a device that emits a shock wave and water. The official said the apartment appears to have three types of explosives: jars filled with accelerants, chemicals that would explode when mixed together and more than 30 "improvised grenades" that resemble commercially available aerial fireworks shells.
Earlier, Carlson told reporters that officials she called "the best of the best" had a plan that included first removing any trip wires, disposing of any incendiary devices and finally doing a controlled detonation that could result in a fire.
Carlson stressed the need to go slow for public safety but also to preserve any evidence that may be inside the apartment.
Fire department vehicles and ambulances were standing by. Chemists also are at the scene to identify chemicals. Power has been cut to the apartment buildings surrounding the area, forcing many people out into shady parking lots to escape the heat.
"It's safe right now with the evacuation. We don't need to rush anything" she said. "We don't want to lose evidentiary value. We're going to be very cautious with how we deal with things."