Prosecutors said they didn't know if he was being medicated. His demeanor, however, angered victims' relatives. Tom Teves, whose son, Alex, was killed in the attack, watched the former doctoral student intently throughout the roughly 12-minute hearing.
"I saw the coward in court today and Alex could have wiped the floor with him without breaking a sweat," Teves said. His son, a physical therapist, dove to protect his girlfriend during the shooting at a multiplex showing The Dark Knight Risesin nearby Aurora in the Denver suburbs.
The court appearance gave millions the chance to scrutinize Holmes' every movement, every flutter of his heavy eyelids.
"It struck me that this is a person who's been through an emotional maelstrom and therefore might be totally wiped out emotionally," said Jeffrey Gardere, an assistant professor of behavioral medicine at Touro College of Osteopathic Medicine.
Gardere said there could be "a psychotic process going on and we see that being acted out there. Or there might be some sort of malingering going on. In other words, trying to make himself look worse than he actually is. Or maybe a combination of all of those things."
The hearing was the first confirmation of Holmes' hair color. On Friday, there were reports that his hair was red and that he told arresting officers that he was The Joker, Batman's nemesis who has brightly colored hair.
Holmes, who police say donned body armor and was armed with an assault rifle, a shotgun, and handguns during the attack, was arrested shortly afterward. His home was booby-trapped with a trip wire, explosives, and unknown liquids that took a day to disarm.
On Monday, security was tight as uniformed sheriff's deputies were stationed outside, including on the roofs of both court buildings.
Holmes' entrance into the courtroom was barely noticeable but relatives of shooting victims leaned forward in their seats to catch a glimpse of him. Two women held hands tightly, one shook her head. One woman's eyes welled up with tears.
Holmes sat down in a jury box, next to one of his attorneys. When the judge asked him if he understood his rights, his attorneys did all the talking.
Christina "Crispy" Blache, who was shot in both legs during the rampage, watched clips of Holmes' court appearance afterward with her father, Robert Blache. Her father said Holmes looked insane, while the restaurant manager said she believed Holmes had no idea what he did.
"He seemed kind of out of it, just sitting there. I don't really know what to think as far as he goes because he didn't seem remorseful or anything," she said.
David Sanchez, who waited outside the courthouse during the hearing, said his pregnant daughter escaped without injury but her husband was shot in the head and was in critical condition.
"When it's your own daughter and she escaped death by mere seconds, I want to say it makes you angry," Sanchez said. He said his daughter Katie Medley, 21, and her husband, Caleb, 23, had looked forward to the movie. Asked what punishment is appropriate if Holmes is convicted, Sanchez said, "I think death is."
At a news conference in San Diego, where Holmes' parents live, their lawyer, Lisa Damiani, was asked if they stood by Holmes, Damiani said, "Yes they do. He's their son."
Holmes is expected to be formally charged next Monday.