URGENT: At least 14 people have been killed and up to 50 injured after a mass shooting at a showing of "The Dark Knight Rises" at a suburban Denver movie theater, police

The violent and chaotic scene erupted about 12:30 a.m. MDT as a gunman stood at the front of one of the Century 16 theaters at the Aurora Mall where the movie "The was playing, police said.

"Witnesses tell us he released some sort of canister. They heard a hissing sound and some gas emerged and the gunman opened fire," Oates said at a news conference.

Police, ambulances and emergency crews swarmed on the scene after frantic calls started flooding the 911 switchboard, officials said.

Officers found the gunman near a car behind the theater.

"A gas mask, rifle, handgun at least one additional weapon (were) found inside" he said.

The suspect was taken into custody, but no name was released. Oates said there's no evidence of any other attackers. There was also no immediate word of any motive.

Earlier reports said there may have been a second shooter, but police believe only one shooter was involved, KDVR tells Fox News.

Witness Hayden Miller told KUSA-TV that he was inside Theater 16 and heard several shots.

"Like little explosions going on and shortly after that we heard people screaming," he told the station.

Hayden said at first he thought it was part of a louder movie next door. But then he saw "people hunched over leaving theater."

Read more: http://www.foxnews.com/us/2012/07/20...#ixzz219waGpqh