Attorneys prepare an insanity defense
Holmes faces 166 counts of murder and attempted murder for the shooting.
Last month, a judge entered a standard plea of not guilty for Holmes.
His parents sat among reporters in the courtroom during Monday's hearing. As the prosecutor announced his plans to pursue the death penalty, Holmes' father put his arm around his mother. Both of them rocked back and forth.
Holmes' attorneys have suggested they intend to pursue an insanity defense.
In the documents filed last Wednesday, his attorneys said they were still exploring a mental health defense, "and counsel will vigorously present and argue any and all appropriate defenses at a trial or sentencing proceeding, as necessary."
Peter Burns was outraged at the possibility of an insanity defense.
His friend, Jessica Ghawi, was among those killed in the movie theater shooting. Holmes' distracted appearance in court, he said, doesn't jibe with the details investigators have revealed about a man who they said created and executed a detailed, deadly plan.
"I think this is an act," Burns told CNN Monday. "I think this coward that shows up every day in court with this aloof look in his eyes that he's just spaced out -- well, I can't imagine somebody pulling off something like this to be in that case. I think as soon as he knows he goes into the courtroom, he knows exactly what's going on."
Burns said he wanted Holmes to receive the toughest punishment possible, but he questioned whether the death penalty -- with the lengthy court proceedings and appeals that come with it -- was the right approach.
"We want justice, but at the same time we want closure," he said. "Do we ever really get closure 17 years down the road?"