Here's a guide to some key questions in the wake of the mass shooting at a Colorado movie theater during a showing of "The Dark Knight Rises."
Q: WHO IS THE SUSPECT?
A: James Holmes, 24, was described as a budding scientist who pursued a graduate program in neuroscience at the University of Colorado Denver.
Holmes had recently taken an intense, three-part oral exam that marks the end of the first year. Those who do well continue with their studies and shift to full-time research, while those who don't do well meet with advisers and discuss their options, including retaking the exam.
Holmes had recently withdrawn from the program, but university officials would not say if he passed the oral exam, citing privacy concerns.
The University of Colorado said it was investigating whether Holmes used his position as a graduate student to order materials in the potentially deadly booby traps that police said they found in his apartment.
Q: WHAT HAPPENED AT HOLMES' APARTMENT?
A: Police disarmed trip wires and explosive devices that authorities said were "set up to kill" people inside the third-floor apartment, which is about four miles from the theater. They removed "all hazards" and authorities entered the building, carrying away a computer at one point.
Q: WHO DIED IN THE SHOOTING?
A: — Veronica Moser-Sullivan, 6
— Alexander J. Boik, 18
— Micayla Medek, 23, of Westminster, Colo.
— Jessica Ghawi, 24, of Denver
— Alexander C. Teves, 24, of Phoenix
— Jonathan T. Blunk, 26, of Aurora
— Matt McQuinn, 27, of Denver
— Alex Sullivan, 27, of Aurora
— John Larimer, 27, of Buckley Air Force Base
— Jesse Childress, 29, of Thornton, Colo.
— Rebecca Ann Wingo, 32, of Aurora
— Gordon W. Cowden, 51, of Aurora.
Q: WAS THERE ANY LINK BETWEEN THE SHOOTING AND THE MOVIE?
A: It's unclear. New York City's police commissioner said he was told the gunman had painted his hair red and called himself the Joker — Batman's nemesis — but Aurora police would not confirm that.
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. But violent attacks on the public by villains are key components of most superhero movies.
There are general parallels to the shooting, "The Dark Knight" and the comic book character. Bruce Wayne's drive to become Batman arose from witnessing the deaths of his parents at the hands of a criminal who shot and killed them after they left a movie. The Batman video game called "Arkham City" takes place in an abandoned movie theater.
Q: HOW MANY GUNS DID THE SUSPECT HAVE?
A: Four. Officers found an AR-15 assault rifle — the civilian form of the M-16, a Remington 12-gauge shotgun and a .40-caliber Glock handgun in the theater, and another identical handgun in the car. The gunman also set off two devices that released smoke or an irritant, Aurora Police Chief Dan Oates said.
Q: WHEN WAS THE LAST MASS SHOOTING IN THE U.S.?
A: The massacre in Aurora was one of the deadliest in the U.S., and the worst mass shooting in the U.S. since the Nov. 5, 2009, attack at Fort Hood, Texas, when an Army psychiatrist killed 13 soldiers and civilians and wounded more than two dozen others.
In Colorado, it was the deadliest shooting since April 20, 1999, when two students opened fire at Columbine High School in the Denver suburb of Littleton, killing 12 classmates and a teacher and wounding 26 others before killing themselves.