Oates said authorities believe they have "eliminated the major threats" inside Holmes's apartment at 1690 Paris Street in Aurora, though they're not finished yet. He has said the apartment was full of bottles of liquid and trip wires.
Jim Yacone of the FBI described the steps taken at the apartment: "A robot, bomb technicians and dynamic explosive disruption tools were used to render safe multiple booby traps and improvised explosive and/or incendiary devices that were contained inside the residence.
"We first had to make entry with a robot," he continued, "and once we got rid of that first booby trap, which was really a wire across the front door, we then had to neutralize a hyperbolic mixture ... and some fuel that we saw immediately inside.
"Once that was disrupted, the technicians did just a marvelous job," Yacone said. "They went to the next IED or IID filled with an unknown substance and they had to attack a triggering mechanism, and they did that very, very skillfully. We then saw multiple containers with accelerants and what appears to be additional triggering mechanisms.
"It went very. very well," he went on. "The threat has not been completely eliminated. It has been significantly reduced. We still have bomb technicians and evidence response recovery folks that literally have to go in there and handle unknown substances with potentially explosive or incendiary outcomes.
"An extensive amount of evidence is in the process of being collected," Yacone added, "and we will bring this portion of the investigation to a close and allow the families back into their homes probably by tomorrow. All evidence will be sent to the Terrorist (Explosive) Device Analytical Center at the FBI's lab in Quantico (in Virginia)."
Yacone explained that the process was phased in order to preserve any evidence in the apartment. "If something should go wrong in the next phase of operations, unplanned, we would have lost that evidence," he said. "So it was a very slow and methodical progression with an effort to preserve the evidence at each phase of that operation."
In response to a question about what would have happened if a neighbor had gone into Holmes's apartment, Yacone said, "It was an extremely dangerous environment. If a neighbor or unassuming pedestrian had walked in that door or, God forbid, a first responder, they would have sustained significant injuries and/or lost their life."
Yacone described the devices in Holmes's apartment as "sophisticated." As for how the 24-year-old obtained the materials to build them, Oates said investigators have learned that he "had a high volume of deliveries" of packages to both his home and workplace over the last four months. "We think 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.
"What we're seeing here, I think, is some evidence of calculation and deliberation."
Holmes legally purchased four guns at local gun shops over the past two months, Oates said yesterday. He also bought more than 6,000 rounds of ammunition on the Internet.
As for the Century 16 theater, where the shooting occurred, Oates said investigators expect to be done processing the scene by Monday. He said they're working to return the belongings left behind by moviegoers in the chaos, such as purses and wallets.