The suspect in a the mass shooting inside an Aurora, Colo., movie theater had booby trapped his apartment and police are still trying to determine how best to search it, according to the police chief of the town.
The explosives appear "very sophisticated" and police could be at the scene for hours or days, according to Aurora Police Chief Dan Oates has confirmed.
"His apartment is booby-trapped," Oates told member of the press. "We are trying to determine how to disarm the flammable or explosive material. We could be here for hours or days. The pictures are fairly disturbing. It looks very sophisticated, how it's booby-trapped. It could be a very long wait."
The masked gunman, identified as James Holmes, killed at least 12 people and wounded at least 38 others — including a 3-month-old infant — when he threw tear gas and opened fire at a showing of the new Batman film "The Dark Knight Rises" in the Denver suburb early Friday, police said.
Denver's KOA radio station said a figure in a gas mask had opened fire at the showing in a mall in the suburb of Aurora and set off a smoke or tear gas bomb before shooting erupted.
"This is a horrific event," Aurora Police Oates told a news conference, adding that a suspect was in custody and that there was no evidence of a second gunman.
Holmes is in custody.
A federal official told the Associated Press that Holmes, 24, had bought a ticket to the midnight showing and went into the theater with the crowd.
He is believed to have propped open an exit door as the movie started, put on protective gear, hurled a gas canister into the theater and opened fire.
He reportedly had three weapons — an AR-15, a Remington shotgun and a .40 Glock — and sprayed the theater at a midnight showing.
Dozens of police and more than 100 FBI agents were on the scene. Authorities evacuated the area while they checked if there was an explosive device in the area.
CNN quoted one witness as saying he saw a "guy slowly making his way up the stairs and firing, picking random people."
Police arrested Holmes in the parking lot behind the theater. "He did not resist, he did not put up a fight," Police Spokesman Frank Fania said. The suspect's apartment building has been evacuated and police were searching the complex after the shooter made comments about possible explosives there.
Holmes was carrying a knife, a rifle, and a handgun when arrested and another gun was recovered from the theater, he said. The gunman was also wearing a bulletproof vest.
The gunman "appeared at the front of the screen" in the theater and started shooting, Fania said.
A witness told CNN: "We heard anywhere from 10 to 20 shots and little explosions going on. Shortly after that we heard people screaming. Then they came on PA system and said everyone needed to get out. As soon as we got out, there were people running around and screaming."
Another witness said the gunman opened fire during a shoot-out scene in the movie, leading to confusion. The theater also filled with thick smoke, he said.
Fania said police received the first call about the shooting at 12:39 a.m. local time and responded within "a minute or two."
Authorities confiscated all cellphones in the theater and were not allowing any vehicles in the parking lot to leave, according to news reports.
Aurora is on the outskirts of Denver and is about 25 miles from Littleton, Colorado, the scene of one of the worst school shootings in the U.S. at Columbine High School.
Local hospitals were alerted to a "mass casualty incident." Media reports said 10 people died at the scene. Many of the injured were said to be in "grave" condition. The youngest victim to be taken to the hospital was reported to be age 3-months-old and a 6-year-old is also believed to be among the injured.
The Pentagon confirmed members of the military were among the casualties inside the theater, and possibly among the injured. Buckley Air Force Base is in Aurora.
A spokeswoman for Denver's Swedish Medical Center said three people had been admitted to that hospital with gunshot wounds and were in critical condition.
Another hospital, Denver Health, had received six wounded, one of whom was in critical condition, spokeswoman Kalena Wilkinson said.
President Barack Obama said he and first lady Michelle Obama were "shocked and saddened" by the shooting and pledged the administration's support for victims of the shooting. He was campaigning in Florida, but cancelled a event scheduled Friday .
"As we do when confronted by moments of darkness and challenge, we must now come together as one American family," the White House quoted the president in a press release.
In a televised speech later in the morning, the president sought to reassure the country.
“The federal government stands ready to do whatever is necessary to bring the perpetrator of this horrendous crime to justice," he said. "“We may never understand what leads anyone to terrorize their fellow human being like this. Such violence, such terror, is senseless.”
Mitt Romney, the Republican presidential hopeful, said he was “praying for the families and loved ones of the victims during this time of deep shock and immense grief.”
Police around the nation were beefing up security of screenings of "The Dark Knight Rises" in response to the Aurora shootings, according to reports.
"As a precaution against copycats and to raise the comfort levels among movie patrons in the wake of the horrendous shooting in Colorado, the New York City Police Department is providing coverage at theaters where the 'The Dark Knight Rises' is playing in the five boroughs," said an NYPD alert.
The movie is rated PG-13 and there were many children at the sold-out show, including some in costumes, at the Century 16 Movie Theaters at the Aurora Town Center. One of the dead was a 3-month-old child, the Denver Post reported.
Police brought witnesses who were unhurt to nearby Gateway High School. Police formed a security perimeter around the school, stationing cruisers throughout its parking lot. About 6:30 a.m. local time a man left the auditorium in a blood-drenched shirt and was driven away in a police cruiser.
Evelyn Marquez, 20, and her boyfriend, Fernando Santos, 20, said in an interview today that the theater was packed.
They were sitting in the middle section when about 30 minutes into the movie a man clad in black entered through an exit door, stood near them, and threw the bomb down some stairs. No one moved.
“It took us a couple of seconds to really realize what was going on,” Santos said.
The theater filled with acrid smoke and breathing became difficult, he said.
The man lifted what they thought was a stick. It was a gun. Santos and Marquez hit the ground and people began crawling over them, she said. Sparks flew off seats behind them, Santos said. He said he saw people struck by bullets.
They crawled to an exit.
Jennifer Seeger, 22, who is studying to be an emergency medical technician, said the man pointed his gun at her. She said she dove to the ground and sensed bullets flying by her face.
One teenage victim, she said, had a bullet in his back.
“I felt his pulse,” she said. “It was really weak. Everyone said ‘Run, run.’ I tried to pull him out, but he was too heavy.”
Emma Goos, 19, a student at St. John’s College in New Mexico, said she lost a shoe trying to escape the theater. She said people slipped on a theater floor greasy with popcorn butter.
Police, she said, were weeping in the parking lot.
A mortician summoned to the scene told Channel 7 that the bomb consisted of metal shards and pepper spray or pepper gas.
Bullets and shrapnel pierced the wall of an adjoining theater, witness Hayden Miller told 9News. Several children were among the victims, the television channel said.
Oates said the suspect was arrested in a car at the mall and that a search of his apartment, also in Aurora, uncovered more explosives. CNN reported that authorities seized an assault weapon, a rifle and two handguns.
Holmes had no history with police other than a traffic ticket, 9News reported.
Miller, the witness, told 9News that the scene was “surreal and scary.”
“It was something like you would see in a movie,” he said.
© 2015 Newsmax. All rights reserved.