CENTENNIAL, Colo. (Reuters) - The man accused of killing a dozen people in a Colorado movie theater during a showing of the new "Batman" film gave little away in his first court appearance on Monday, sitting silently in a red jailhouse jump suit and with his hair dyed bright red.

James Eagan Holmes, 24, who was detained immediately after the massacre early on Friday morning, appeared groggy and emotionless during the brief hearing, looking straight ahead and occasionally closing his eyes. He was shackled at the wrists and ankles.

About 40 members of the victim's families were seated on the left side of the courtroom. One family member seated in the front row glared at Holmes throughout the entire proceeding.

Several times when Arapahoe County District Judge William Sylvester asked Holmes a question, one of his attorneys answered for him.

Police say Holmes was dressed in body armor and toting three guns when he opened fire at a packed midnight screening of the new Batman movie at a theater complex in the Denver suburb of Aurora in the early hours of Friday. Fifty-eight other people were wounded, and many of them have serious injuries.

The former neuroscience student also left his apartment booby-trapped with explosives that police said could have destroyed the apartment complex. They conducted a controlled detonation over the weekend.

Police say they are still searching for a motive for the crime, which baffled fellow students and acquaintances. They described him as a quiet high-achiever whose past gave little inkling that anything was amiss.

At the hearing the judge set a date of next Monday for formal charges to be filed.

POSSIBLE DEATH PENALTY

Arapahoe County District Attorney Carol Chambers said she would consult with the victims and families of the dead before making a decision on seeking the death penalty.

She told reporters outside the court house that the decision on the death penalty had to be made within 60 days of his arraignment, "so it's months down the line."