A heavily armed man entered a movie theater in suburban Denver early Friday and opened fire, killing at least 12 people and injuring 50 others.
The incident, which took place about 12:30 a.m. at the Century 16 movie theater in Aurora, Colo., occurred during midnight screenings of the new Batman film "The Dark Knight Rises."
"This is a horrific event," Aurora Police Chief Dan Oates said during a news conference.
The gunman, who was wearing a gas mask, reportedly set off a smoke or tear gas bomb then walked up to the front of the screen in one of the theaters and opened fire.
When the movie patrons realized the attack was real and not part of the movie, pandemonium erupted and they began to flee. The film continued to play on the screen as bloodied customers took refuge outside. According to witnesses on the scene, some of the bullets also went through the walls of an adjacent theater, injuring patrons.
“There was this one guy on all fours crawling. There was this girl spitting up blood. There were bullet holes in some people’s backs, in some people’s arms. There was one guy who was just stripped down to his boxers. It looked like he had been shot in the back or something,” Donovan Tate, who escaped from the packed theater with his girlfriend, told CBS4.
Soon after receiving a flood of 911 calls, hundreds of police officers, ambulance and emergency crews arrived on the scene.
The suspect was found near a car behind the theater and arrested. He was dressed in black, carrying a knife, rifle and a handgun, and wearing a bulletproof vest.
"He did not resist," police spokesman Frank Fania. "He did not put up a fight."
The shooter's identity has not been released but he is thought to be in his early 20s. A motive for the attack is unknown.
Police also searched the suspect's North Aurora home after he spoke of "possible explosives in his residence," Oates said. Authorities evacuated the building as a precautionary measure.
The police originally announced that 14 people had been killed in the attack, but revised the death toll around 7:45 a.m. ET, NBC News reported.
At this time, there is no evidence of additional shooters.
President Barack Obama, who is in Palm Beach, Fla., was notified of the shooting by Homeland Security Advisor John Brennan at 5:26 a.m. ET. He released the following statement:
"Michelle and I are shocked and saddened by the horrific and tragic shooting in Colorado. Federal and local law enforcement are still responding, and my Administration will do everything that we can to support the people of Aurora in this extraordinarily difficult time. We are committed to bringing whoever was responsible to justice, ensuring the safety of our people, and caring for those who have been wounded. As we do when confronted by moments of darkness and challenge, we must now come together as one American family. All of us must have the people of Aurora in our thoughts and prayers as they confront the loss of family, friends, and neighbors, and we must stand together with them in the challenging hours and days to come."
GOP challenger Mitt Romney said he and his wife Ann are "deeply saddened" by the shooting.
"We are praying for the families and loved ones of the victims during this time of deep shock and immense grief. We expect that the person responsible for this terrible crime will be quickly brought to justice."
The theater where the attack took place is just about 25 miles from Columbine High School, where two students shot and killed 13 people in 1999.
This story is developing...
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