(Newsroom America) -- Authorities have eliminated all major threats in the apartment of James Holmes, the 24-year-old suspect accused of killing 12 people and wounding scores more during a shooting spree early Friday morning at a midnight screening of the new Batman movie in Aurora, Colo.
Reports said police and explosives ordnance personnel on Saturday managed to successfully disarm all trip wires and other devices in his booby-trapped apartment.
Holmes allegedly went on a killing rampage as a midnight opening of "The Dark Knight Rises" began in a packed local theater. Reports have said he was packing as many as 6,000 rounds of ammunition when he when arrested.
Early reports said Holmes told police upon his arrest his apartment was booby trapped with several explosive devices, but he became uncooperative afterward.
Police evacuated Holmes' apartment building and several surrounding buildings in response.
Aurora police Sgt. Cassidee Carlson said the first booby trap encountered was "meant to kill" the first person who opened the front door to the apartment.
"This is some serious stuff that our team is dealing with," she told reporters.
Witnesses have reported hearing two small detonations during the disarming process.
Several unknowns remain in the apartment, reports have said, including jars with possible accelerants, balloons filled with gunpowder and bullets scattered about the apartment floor.
The operation to clear the apartment of explosive devices will occur in three phases, and police have said it's unclear how long it will take to complete all three.
"There is no timeline, there is no end time," Carlson said.
It was clear in the aftermath, investigators say, that Holmes planned his attack well.
From what he was wearing - a ballistic helmet, bulletproof vest and shin guards, as well as a gas mask - to his use of smoke bombs, his booby-trapped apartment and his method of attack, Holmes clearly spent a great deal of time preparing.
Police said the night of the premier Holmes bought a ticket and entered the theater he later attacked and propped open an exit door as the film played.
Authorities said Holmes had purchased four guns within the past 60 days, along with 6,000 rounds of ammunition, all of which were bought legally.
© 2012 Newsroom America.