In an absolutely terrifying and tragic story, 12 people are dead and at least 50 are injured after a gunman entered a screening of The Dark Knight Rises in Aurora, Colorado, threw a tear gas canister and began opening fire on the audience. From ABC News:

The suspect, James Holmes, 24, of Aurora, was caught by police in the parking lot of the Century 16 Movie Theaters, nine miles outside Denver, after police began receiving dozens of 911 calls at 12:39 a.m. MT. Police said the man appeared to have acted alone.

Witnesses in the movie theater said Holmes crashed into the auditorium through an emergency exit about 30 minutes into the film, set off a smoke bomb, and began shooting. Holmes stalked the aisles of the theater, shooting people at random, as panicked movie-watchers in the packed auditorium tried to escape, witnesses said.

"You just smelled smoke and you just kept hearing it, you just heard bam bam bam, non-stop. The gunman never had to reload. Shots just kept going, kept going, kept going," one witness told ABC News.

"I'm with coworkers and we're on the floor praying to God we don't get shot, and the gunshots continue on and on, and when the sound finally stopped, we started to get up and people were just bleeding," another theatergoer said.

CNN is reporting that a 3-month-old was among those shot, as well as a 9-year-old. Also:

Warner Bros., the studio behind the movie, said the company and filmmakers were "deeply saddened" to learn of the incident. The studio canceled the movie's Paris premiere, while New York police Commissioner Raymond Kelly said his officers would watch over screenings of "The Dark Knight" to prevent copycat shootings.

According to the New York Times, the suspect Holmes told police that he had explosives in his apartment, which authorities are currently investigating. Also:

A witness told CNN affiliate KUSA that he was in one of the other theaters showing the movie. “It’s crazy to think I could have been in the other line,” he said.

“We were watching a scene of the movie — it was a shootout scene, there were guns firing,” he said. “Then loud bangs came from the right of the theater. Smoke took over the entire theater, and it was really thick and no one could really see anything. Me and my sister were sitting there wondering what was going on. Five people were limping, wounded, slightly bloody.”

“I saw a girl who was pretty much covered in blood. It made me think the worst,” the man said. “A cop came walking through the front door before everyone was cleared up and before everything was completely under control holding a little girl in his arms, and she wasn’t moving.”

More to come.