Officials also turned to the Internet in an effort to make sense of the events.
The Red Cross is asking people who witnessed the shooting to tell loved ones that they were OK over social media sites like Facebook and Twitter.
"People don't know how close you were, so help alleviate that anxiety," spokeswoman Patricia Billinger told USA Today.
And other officials used the Internet to offer sympathy.
"We certainly appreciate the nation's thoughts and prayers as our police department continues to investigate the terrible theater shooting tragedy that occurred today," the city of Aurora wrote on its Facebook page. "Our condolences go out to the victims and their family members."