(AURORA, Colo.) -- Suspected Colorado movie theater gunman James Holmes purchased four guns at local shops and more than 6,000 rounds of ammunition on the Internet in the past 60 days, Aurora Police Chief Dan Oates told a news conference Friday evening.
"All the ammunition he possessed, he possessed legally, all the weapons he possessed, he possessed legally, all the clips he possessed, he possessed legally," an emotional Oates said.
Authorities have yet to identify all of the 10 victims who died at the theater. Two other people died at the hospital, for a total of 12 dead. Thirty people remained hospitalized, 11 of them critical, Oates said.
A total of 70 people were injured, most of them by gunfire but a "handful" during the ensuing chaos, Oates said. One person was hit in an adjacent theater.
Gov. John Hickenlooper opened the news conference Friday evening, saying, "We are seeing this community rise up and do the things that communities do."
At times lost for words, he repeatedly praised the efforts of the first responders.
The shooting occurred during a sold-out midnight premiere of the new Batman movie, The Dark Knight Rises, when Holmes, 24, allegedly unloaded four weapons' full of ammunition into the unsuspecting crowd.
The number of casualties makes the incident the largest mass shooting in U.S. history.
Holmes, an honors student and Ph.D. candidate at a nearby college with a clean arrest record, allegedly entered the movie auditorium wearing a ballistics helmet, bulletproof vest, bulletproof leggings, gas mask and gloves. He detonated multiple smoke bombs, and then began firing at viewers in the sold-out auditorium, police said Friday.
Holmes, who is being held in jail, is originally from Riverside, Calif., where he attended the University of California branch, Oates told reporters at a news conference Friday evening. "The suspect lived alone and he kept to himself," Oates added.
Bullets from the spree tore through the theater and into adjoining theaters, where at least one other person was struck and injured. Ten members of The Dark Knight Rises audience were killed in the theater, while two others died later at area hospitals. Numerous patrons were in critical condition at six local hospitals, the Aurora police said Friday afternoon.
Authorities began removing the bodies that afternoon, according to ABC News Denver affiliate KMGH-TV. Several people have been reported missing as the coroner identifies the dead.
Holmes was apprehended within minutes of the 12:39 a.m. shooting at his car behind the theater, where police found him in full riot gear and carrying three weapons, including an AR-15 assault rifle, which can hold upwards of 100 rounds, a Remington 12-gauge shotgun, and a .40 Glock handgun. A fourth handgun was found in the vehicle.
Agents from the federal bureau of Alcohol, Tobacco, and Firearms are tracing the weapons.
According to police sources, Holmes told the officers arresting him that he was "The Joker," referring to the villain in the second installment of the Batman movie trilogy, The Dark Knight. He also warned police that he had booby-trapped his apartment, leading officers to evacuate the Aurora apartment building.
Chief Oates earlier Friday said that police, bomb squads and the ATF have found a large number of explosive devices and trip wires at Holmes' apartment and have not yet decided how to proceed without setting off explosions.
"The pictures we have from inside the apartment are pretty disturbing considering how elaborate the apartment is booby trapped," police said outside of the apartment complex. The "flammable and explosive" materials could have blown up Holmes' apartment building and the ones near it, police said.
The apartment complex is home exclusively to University of Colorado Medical Center students, patients and staff members, residents told ABC News.
Oates Friday evening said police will allow residents to retrieve personal belongings but leave the booby-trapped apartment alone for now, and inspect them Saturday with the help of federal law enforcement. Residents are staying at a local high school in the meantime. Oats didn't know many people are displaced from the five apartment buildings involved.
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