AURORA, Colo. -

Police in Colorado say a man suspected of shooting 71 people at a Colorado viewing of the Batman movie "The Dark Knight Rises" told police he was the Joker, a villain from another Batman movie.

Police said 71 people were shot in the suburban Denver movie theater early Friday during midnight shows of the movie.

Twelve people were killed, 10 of them at the theater. Another 59 adults and children were wounded.

The U.S. Department of Defense said Friday afternoon that two U.S. airmen and one sailor were wounded in the attack, and another sailor remains unaccounted for.

Aurora Police Chief Dan Oates said there were four showings of the movie at the time and all were sold out. He did not know how many people that amounts to.

Oates said investigators are confident the gunman acted alone.

Police arrested 24-year-old James Holmes, whose apartment four miles away was booby trapped with chemical devices and trip wires. Investigators said it could take hours or days to search the apartment.

ABC News reported that police said Holmes had dyed his hair red and told police he was the Joker, the villain played by Heath Ledger in the previous Batman film, "The Dark Knight." The Joker is usually depicted in comic books and Batman movies with green hair.

A law enforcement official briefed on the investigation told The Associated Press on Friday afternoon that Holmes has asked for a lawyer. The official spoke on condition of anonymity to discuss the ongoing case.

Oates said Holmes used an AR-15 assault rifle, a Remington shotgun and a .40-caliber Glock handgun, and investigators found a fourth gun in Holmes' Hyundai, which was parked in back of the theater.

A U.S. official said Holmes bought a ticket to a midnight showing of "The Dark Knight Rises" and went into the theater as part of the crowd.

A federal law enforcement official said Holmes is believed to have propped open an exit door in the theater as the movie was playing, donned protective ballistic gear and opened fire. The official spoke on the condition of anonymity to discuss the ongoing investigation.

At the time of the attack, police said Holmes was wearing a ballistic helmet, a vest, leggings, a throat protector, a groin protector, a gas mask and black tactical gloves.

Holmes had a traffic summons for speeding in October 2011, and that is the extent of his history with the law.

President Barack Obama, who was in South Florida, says he is "shocked and saddened" by the deadly shooting. He is urging the nation to "come together as one American family."

Read the president's full statement here.

The president also announced he will return to the White House, cancelling all Florida events scheduled for Friday.

Mitt Romney also released a statement, saying he is "deeply saddened by the news of the senseless violence."

Read Romney's full statement here.

Aurora is located on the southeast outskirts of Denver, about 10 miles from downtown.

On Friday afternoon, police evacuated two research buildings at the University of Colorado Anschutz Medical Campus, where the suspect in the Colorado shootings was a graduate student.

University of Colorado-Denver Police Chief Doug Abraham sent a campus-wide email Friday ordering all nonessential personnel to leave the campus or stay home.

Abraham said it's a precaution and there is no reason to believe staff or students are at risk. The evacuation order is in effect until 6 a.m. Saturday.

Abraham said Holmes' building access was terminated in June and that he was in the process of completing withdrawal paperwork.