CENTENNIAL, Colo. — Attorneys for the suspect in the Colorado movie theater shootings said Thursday their client is mentally ill and that they need more time to assess the nature of his illness.

James Holmes’ lawyers made the disclosure at a court hearing in suburban Denver where news media organizations asked a judge to unseal documents in the case.

Holmes, a 24-year-old former Ph.D. student at the University of Colorado, Denver, had the familiar, dazed demeanor that he had in previous court appearances.

Holmes is accused of going on a July 20 shooting rampage at a midnight showing of the latest Batman movie in Aurora, killing 12 people and injuring 58 others.

Defense attorney Daniel King made the revelation about Holmes’ illness as he argued that the defense needs more information from prosecutors and investigators to assess their client.

“We cannot begin to assess the nature and the depth of Mr. Holmes’ mental illness until we receive full disclosure,” he said.

King said Holmes sought out university psychiatrist Lynne Fenton for help. A hearing was scheduled for Aug. 16 to establish whether there was a doctor-patient relationship between them.