CENTENNIAL, Colo. (AP) — As the suspected gunman in the Colorado theater massacre headed to his first court appearance Monday, authorities have disclosed that he is refusing to cooperate and that it could take months to learn what prompted the horrific attack on midnight moviegoers at a Batman film premiere.

James Holmes has been held in solitary confinement at an Arapahoe County detention facility since Friday but was moved to a nearby courtroom for a 9:30 a.m. MDT hearing, where he heard the pending charges against him. Holmes is being held on suspicion of first-degree murder, and he could also face additional counts of aggravated assault and weapons violations.

Prosecutors will have 72 hours from the hearing to formally charge the 24-year-old Aurora resident originally from California.