Meanhwile, the movie industry is scrambling too to react to security and other issues the shooting raises.
What do we know about the shooter?
Shortly after the Denver-area shootings, 24-year-old James Holmes was taken into custody by police.
Holmes had an assault rifle, a shotgun and two pistols, a federal law enforcement official said.
FBI agents and police used a hook and ladder fire truck to reach Holmes' apartment in Aurora, police Chief Dan Oates said. They put a camera at the end of a 12-foot pole inside the apartment, and discovered that the unit was booby trapped. Authorities evacuated five buildings as they tried to determine how to disarm flammable and explosive material
Police released a written statement from Holmes' family: "Our hearts go out to those who were involved in this tragedy and to the families and friends of those involved."
In Colorado, A neuroscience graduate student in a gas mask barged into a crowded Denver-area theater during a midnight showing of the Batman movie on Friday, hurled a gas canister and then opened fire, killing 12 people and injuring at least 50 others in one of the deadliest mass shootings in recent U.S. history.
It's unclear whether the shooter's motives had any specific link to "The Dark Knight Rises." The shooting happened at 12:30, not far into the midnight screening that marked the film's opening day.
Violent attacks on the public by villains are key components of most superhero movies, including "The Avengers" and "The Amazing Spider-man," both in theaters now. By Hollywood standards, the Batman movies are more grim than bloody.
But there are general parallels to the Colorado shooting, "The Dark Knight" and the comic book character:
Bruce Wayne's drive to become Batman arose from witnessing the deaths of his parents, Thomas and Martha Wayne, at the hands of small-time criminal Joe Chill, who shot and killed them after they had left a movie theater.
The Batman video game called "Arkham City" takes place in an abandoned movie theatre (The Monarch, outside of which Bruce Wayne's parents were killed).
In the third issue of DC Comics' "Batman: The Dark Knight," a gritty retooling of the Batman character that was written by Frank Miller in the 1980s, the Joker kills an entire late-night TV audience with gas.
In the same book, a man starts shooting up a porn theater after getting fired from his job.
-"The Dark Knight Rises" features at least two scenes where unsuspecting people are attacked in a public venue: the stock exchange and a football stadium
quot;Warner Bros. and the filmmakers are deeply saddened to learn about this shocking incident. We extend our sincere sympathies to the families and loved ones of the victims at this tragic time," the studio said.
Workers dismantle an installation setup for the premiere of "The Dark Knight Rises", scheduled to be held Friday night in Paris, Friday, July 20, 2012, which has been canceled after a gunman killed 12 people at a Colorado opening of the same film.
PARIS (AP) -- The Paris premiere of the new Batman movie "The Dark Knight Rises" was canceled Friday after a gunman killed at least a dozen people at a Colorado opening of the same film.
The event at a movie theater on the French capital's famed Champs-Elysees Avenue was supposed to include director Christopher Nolan and various stars on a red carpet
But on Friday afternoon, workers were pulling down the red carpet display. Some could be seen carrying away a large mask that had adorned the facade of the theater.
Warner Bros. said in a statement that it was also canceling all media interviews in the city. The studio said it was "deeply saddened" by the shooting.
"Warner Bros. and the filmmakers are deeply saddened to learn about this shocking incident," read a statement from Warner Bros. "We extend our prayers and deepest sympathies to the victims, their loved ones and those affected by this tragedy."
The studio was rushing to react to the tragedy. Dan Fellman, head of distribution for Warner Bros, said he had been up since 4 a.m. making calls.
"Everybody is very saddened by the event. We were obviously looking for a very happy occasion for us," Fellman said. "It's a difficult way to begin. We're just more concerned now with the well-being of those that were injured, of course."
The studio had no further comment on whether screenings might be canceled, or precautions taken. Director Christopher Nolan and actor Christian Bale did not immediately respond to requests for comment.
Cinemark Holdings, Inc., the chain that owns the theater where the shooting happened, said it was deeply saddened by the tragedy.
"Our thoughts and prayers are with the victims, their families and loved ones, our employees, and the Aurora community. We are grateful for the quick and professional reaction of all local law enforcement and emergency responders. Cinemark is working closely with the Aurora Police Department and local law enforcement," the company said.
Movie theaters around the country continued Friday showings of the film as planned.
The National Association of Theatre Owners issued a statement offering their "hearts and prayers" to the victims. The association said, "Guest safety is, and will continue to be a priority for theater owners," adding that the group would work closely with law enforcement and review security procedures.
"We share the shock and sadness of everyone in the motion picture community at the news of this terrible event," said Sen. Chris Dodd, chairman and CEO of the Motion Picture Association of America. "We extend our prayers and deepest sympathies to the victims, their loved ones and all those affected by this tragedy."
"The Dark Knight Rises" had expectations of being one of the biggest weekend openings ever. The previous installment, "The Dark Knight," earned a then-record $158.4 million in its first three days, including $18.5 million from midnight screenings.
Fellman said the studio still planned to release early box-office results Friday of the roughly 3,700 theaters domestically that began showing "The Dark Knight Rises" at midnight. The film expanded into its full domestic debut of 4,404 cinemas nationwide Friday.
Paul Dergarabedian, an analyst for Hollywood.com who specializes in box office, declined to speculate on an effect the tragedy might have on the film over the weekend. But some moviegoers were already rethinking their plans.
Christine Cooley, who works for the University of Florida at a campus facility near Tampa, Fla., said she and her 15-year-old daughter were stunned by the TV coverage of the shooting Friday morning.
"Her immediate reaction was `I'm never going to the movie theater again. Why should I go somewhere where I'm looking over my shoulder worrying that someone is going to come in and harm us when I can wait six months and watch it in the safety of my own home?'"
Cooley said she tried to explain to her daughter that it was an isolated incident, "but I see where she's coming from. Why put yourself in harm's way."