Memories of Columbine

Holmes will be represented by James O'Connor, head of the Arapahoe County Public Defender's Office, Robinson said.

The mass shooting evoked memories of the 1999 massacre at Columbine High School in Littleton, 17 miles (27 km) from Aurora, where two students opened fire and killed 12 students and a teacher.

A memorial of flowers, candles and stuffed animals quickly sprung up where the shooting rampage took place. A handwritten sign read: "7/20 gone not forgotten."

Isaac Pacheco (C) is comforted after leaving a birthday card for his friend Alex Sullivan, who was killed in the Denver-area movie killings, at a memorial site for victims behind the theater where a gunman opened fire on moviegoers in Aurora, Colorado, July 21, 2012. [Photo/Agencies]

The University of Colorado Hospital, which treated some of the shooting victims, said 10 people had been discharged and five remained in critical condition.

The Medical Center of Aurora said four of its seven patients remained in the intensive care unit, while three others were on the main trauma floor.

Those who witnessed the shooting told of a horrific scene, with dazed victims bleeding from bullet wounds, spitting up blood and crying for help.

"I slipped on some blood and landed on a lady. I shook her and said, 'We need to go; get up,' and there was no response, so I presumed she was dead," said Tanner Coon, 17.

An eye witness reacts while being interviewed about an overnight shooting that killed 12 people at a midnight premiere of the new "Batman" movie in Aurora, Colorado, July 20, 2012. [Photo/Agencies]