The Colorado theatre shooting suspect has made his first court appearance with a dazed expression and bright orange hair.

James Holmes, wide-eyed and unshaven, appeared Monday after being accused of the shooting rampage that killed 12 people and injured 58.

He will be formally charged next Monday.

Authorities say the 24-year-old former graduate student is refusing to co-operate, and it could take months to learn what prompted Friday's attack on moviegoers at a midnight screening of the latest Batman film.

Investigators say they found a Batman mask inside Holmes' booby-trapped apartment.

Holmes has been held in solitary confinement since Friday.

Prosecutors say they may consider the death penalty, but will make that decision after consulting with victim's families.

Holmes told arresting officers he was the joker.