James Holmes, the 24-year-old alleged to have gunned down 12 people in a US cinema screening the new Batman movie, made his first appearance in a Colorado court Monday.

With orange hair, Holmes sat glum-faced, his eyes repeatedly closing and opening in strange fashion, at the proceedings in Centennial, following the massacre on Friday in a movie theater in Aurora.

Holmes, wearing a maroon prison jumpsuit, stared blankly as lawyers discussed procedural arrangements with the Arapahoe County judge. He was later led out after the hearing, which lasted less than 10 minutes.

He is accused of shooting dead 12 people and wounding 58 others at a cinema Friday in Aurora, outside Denver, as young moviegoers packed the midnight screening of the latest Batman film, "The Dark Knight Rises."

Prosecutors are expected to seek the death penalty later this week, although experts note that only one person has been executed in Colorado since 1976, ABC and local media reported.

Police say there is no doubt Holmes committed the atrocity. He gave himself up outside the cinema, still clad in the full body armor that witnesses described the gunman wearing as the bullets flew inside.

The gunman emerged from a fire exit after the film began and threw two canisters of noxious gas into the crowd.

After firing one round directly into the air with a pump-action shotgun, he then began shooting people at random with a military-style assault rifle that could dispatch 50 to 60 rounds a minute, witnesses said.

Holmes has been held in solitary confinement since his arrest.

New York City Police Commissioner Ray Kelly said Holmes had painted his hair reddish orange and claimed he was the Joker, Batman's sworn enemy.