AURORA, Colo. (AP) -- Aurora police have disarmed the trip wire and the first explosive device in the apartment of the suspect in a movie theater shooting.
Aurora police Sgt. Cassidee Carlson says the booby trap was set up to kill the person opening the door.
In her words: "This is some serious stuff that our team is dealing with."
Carlson says there are other devices that need to be disarmed but authorities are reassessing the scene.
She says it's still possible that the team has to detonate the explosives, which could cause a loud boom and fire, but people will be told about it.
The suspect, James Holmes, lives in the third-floor apartment
The FBI and Homeland Security Department said there was no information indicating more shooting sprees were planned at movie theaters around the country, according to an intelligence bulletin obtained by The Associated Press.
Twelve people were killed and 58 were injured in the attack early Friday at the packed Aurora theater outside Denver. A few of those suffered injuries not by gunfire but in the chaos that ensued as the audience tried to flee the smoke-filled theater in a panicked dash for the doors, authorities said. Among the wounded, 11 were listed in critical condition.
After the shooting, police arrested James Holmes, 24, and determined his nearby apartment had been booby trapped, then ordered residents in the building and surrounding homes to evacuate.
Scores of law enforcement officials, including local bomb squad technicians and dozens of federal Bureau of Alcohol, Tobacco, Firearms and Explosives agents gathered again at the apartment Saturday and planned to enter.
"It's safe right now with the evacuations so we don't want to rush anything," said Aurora police Sgt. Cassidee Carlson.
The apartment contains trip wires and jars that may contain accelerants, she said, noting authorities may be forced to detonate the explosives, which could cause a loud boom and a fire.
Police grimly went door to door late Friday with a list of victims killed in the worst mass shooting in the U.S. in recent years, notifying families who had held out hope that their loved ones had been spared.
The deceased victims included 23-year-old Micayla Medek, said Anita Busch, the cousin of Medek's father. The family took the news hard, but knowing her fate after waiting without word brought them some peace, Busch said.
"I hope this evil act, that this evil man doesn't shake people's faith in God," she said.
Besides Medek, relatives confirmed that Alex Sullivan and Jessica Ghawi were among those killed, Sullivan on his 27th birthday.
It remained unclear Saturday what drove the suspect to fire round after round at the unsuspecting audience watching "The Dark Knight Rises." Aurora Police Chief Dan Oates said Holmes used a military-style semi-automatic rifle, a shotgun and a pistol that he had bought at local gun stores within the last two months. He also recently purchased 6,000 rounds of ammunition over the Internet, the chief said.
The suspect's stellar academic record, apparent shy demeanor and lack of a criminal background made the attack even more difficult to fathom.
It also wasn't known why the suspect chose a movie theater to stage the assault, or whether he intended some twisted, symbolic link to the film's violent scenes.
The new Batman movie, the last in the trilogy starring Christian Bale, opened worldwide Friday with midnight showings in the U.S. The plot has the villain Bane facing Bale's Caped Crusader with a nuclear weapon that could destroy all of fictional Gotham.
In New York City, Police Commissioner Raymond Kelly said: "It clearly looks like a deranged individual. He has his hair painted red. He said he was the Joker, obviously the enemy of Batman."
Oates would not confirm that information, but did say he spoke to Kelly. The two used to work together in New York. Asked whether Holmes had makeup to look like the Joker, Oates said: "That to my knowledge is not true."
Near the entrance to the theater's parking lot, a makeshift memorial of 12 candles sat in a row alongside piles of flowers. Up the hill, about 20 pastors led a vigil for about 350 people, some hugging and crying. A sign read, "7/20. Gone Not Forgotten."
An emotional Gov. John Hickenlooper said earlier Friday that people would not be defined by the tragedy.
"We are clear that we are going to rise back and lift ourselves above this," he said.
A federal law enforcement official said Holmes bought a ticket to "The Dark Knight Rises," went into the theater as part of the crowd and propped open an exit door as the movie was playing. The suspect then donned protective ballistic gear and opened fire, the official said, speaking on condition of anonymity because he was not authorized to discuss the investigation.
Authorities said Holmes shot scores of people, picking off victims who tried to flee. At least one person was struck in an adjacent theater by gunfire that went through the wall. Adding to the terror and chaos were two gas canisters thrown by the suspect that filled the theater with smoke.
Tanner Coon, a 17-year-old Aurora resident who was watching the film with two friends, said he first thought the gunshots were firecrackers. When he realized what was happening, he ducked between seats and waited for the shooter to bark demands.
"When is he going to start telling us what to do? When is this going to become a hostage situation?" Coon said.
When the firing ended, Coon said he started running up the row but slipped in blood and fell on a woman who was lying on the ground. He tried shaking her, he said, but she didn't respond, so he left her behind and ran from the theater.
Within minutes, frantic 911 calls brought some 200 police officers, ambulances and emergency crews. Holmes was captured in the parking lot.
Kaitlyn Fonzi, a graduate student at University Hospital who lives in the apartment below, said she heard loud music coming from the suspect's unit just after midnight. She went upstairs and put her hand on the door handle. She felt it was unlocked, but she didn't know if he was there and decided not to confront him.
Fonzi called police, who told her they were busy with a shooting and did not have time to respond to a noise disturbance. She said she was shaken to later learn the apartment was booby trapped.
"I'm concerned if I had opened the door, I would have set it off," she said.
The shooting was the worst in the U.S. since the Nov. 5, 2009, attack at Fort Hood, Texas. An Army psychiatrist was charged with killing 13 soldiers and civilians and wounding more than two dozen others. It was the deadliest in Colorado since the 1999 attack at Columbine High School, where two students killed 12 classmates and a teacher and wounded 26 others before killing themselves.
Holmes had enrolled last year in a neuroscience Ph.D. program at the University of Colorado-Denver, though he left last month for unknown reasons. In academic achievement, "he was at the top of the top," recalled Timothy P. White, chancellor at the University of California, Riverside, where Holmes earned his undergraduate degree before attending the Denver school.
Those who knew Holmes described him as a shy, intelligent person raised in California by parents who were active in their well-to-do suburban San Diego neighborhood. Holmes played soccer at Westview High School and ran cross-country before going to college.
Police released a statement from his family Friday that said, "Our hearts go out to those who were involved in this tragedy and to the families and friends of those involved."
Associated Press contributors to this report include Kristen Wyatt, Steven K. Paulson, Ivan Moreno and Mead Gruver in Aurora; Dan Elliott, Gillian Flaccus, Nick Riccardi and Colleen Slevin in Denver; Tom Hays in New York; Monika Mathur and Jennifer Farrar at News Research Center; and Alicia A. Caldwell and Eileen Sullivan in Washington.