New York police posted officers at dozens of theaters around the city. Ticket-takers at a multiplex in Washington searched moviegoers' bags and purses. And one of the nation's biggest theater chains barred patrons from wearing masks or costumes.
The movie industry grappled Friday with the deadly Colorado shooting at a midnight screening of "The Dark Knight Rises," as one of the most anticipated films in years became enmeshed with a massacre.
In "The Dark Knight Rises," a masked villain leads a murderous crew into a packed football stadium and wages an attack involving guns and explosives. It's just one of the more haunting scenes in what was one of the most anticipated movies in years.
An eager audience forgoing sleep to take in the midnight showing of "The Dark Knight Rises" instead were witnesses Friday to a bloody mass shooting at a suburban Denver movie theater. Police said a man clad in black threw a canister that spewed smoke before he opened fire. Witnesses said that at first, they thought it was a prank or a stunt. Then the gunman shot steadily at the audience, not speaking. Some of their accounts:
Michael Greenberger, director, University of Maryland Center for Health and Homeland Security
Authorities have started to remove the bodies of the 10 people killed early Friday at a suburban Denver movie theater.
Movie giant AMC Theatres says it won't be allowing people to wear costumes or face-covering masks into its theaters after a shooting in Colorado that killed at least 12 people and injured dozens more.
The Paris premiere of the new Batman movie "The Dark Knight Rises" was canceled Friday after a gunman killed several people at a Colorado opening of the same film.
The police chief in the Denver suburb where a gunman opened fire at a movie theater says the suspect was arrested soon after officers arrived.
Police have evacuated two research buildings at the University of Colorado Anschutz Medical Campus where the suspect in the Colorado shootings was a graduate student.
Listen to initial radio traffic from fire and police regarding the movie theater shooting in Aurora, Colo.
The suspect in a mass shooting at a Colorado movie theater was in a doctoral program but was not in medical school.
One of the people witnesses to a mass shooting in a Denver suburb says the shooter "looked like an assassin ready to go to war."
Pentagon press secretary George Little says that it's not yet clear how many military casualties there were, or specifically whether they were killed or injured.
"The Dark Knight Rises" was one of the most anticipated films in recent memory, but now there's a very dark shadow over the film.
Clint Van Zandt, former FBI profiler
See reported cellphone video from the scene of the shooting, along with reported witness accounts.
See reaction below to the shooting at a Colorado movie theater that left 12 dead and dozens more injured.