AURORA, Colorado - US police said Saturday they had cleared "all hazards" from the booby-trapped apartment of James Holmes, who is accused of killing 12 people at a Colorado screening of the new Batman film.
"All hazards have been removed from the Paris Street location," the Aurora Police Department said in a tweet.
It said all residents who were ordered out of the area could now return home, apart from those in the suspected gunman's apartment block. Only the 1600 block of Paris Street remained closed in Aurora city.
All five apartment blocks, including the one where Holmes lived, were evacuated shortly after he allegedly opened fire in a crowded theater showing an opening day midnight screening of "The Dark Knight Rises."
Law enforcement officials indicated earlier that they had disabled the most dangerous explosives and triggering systems laid out methodically in the apartment, aiming to kill police officers or whoever else entered.
Aurora police chief Dan Oates did nothing to hide his fury, saying the complex set of devices aimed to kill police and first responders.
"Make no mistake, this apartment was designed... to kill whoever entered it. And who was most likely to enter that location after he planned and executed this horrific crime? It was going to be a police officer," he told reporters.
"And if you think we're angry, we 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 officers."
The Federal Bureau of Investigation said a remotely-driven robot with cameras was sent into the apartment, cutting first a tripwire and identifying other dangerous devices further into the room.
Maneuvering the robot slowly and methodically, technicians then had to disarm a hyperbolic mixture -- a powerful cocktail containing fuel and an oxidizer -- as well as an explosive or incendiary device filled with an "unknown substance" and a triggering mechanism, FBI special agent in charge Jim Yacone said.
"It was an extremely dangerous environment," he told reporters, adding that if "a neighbor or an unassuming pedestrian would have walked in that door, or God forbid a first responder, they would have sustained significant injuries and/or lost their life."
Evidence collected at the site will be sent to the Terrorist Explosive Device Analytical Center at the FBI's laboratory in Quantico, Virginia, for analysis.
"Multiple booby traps and indoor incendiary devices" at the apartment were rendered safe, Yacone said.