CENTENNIAL, Colo. — James E. Holmes showed no visible reaction Monday as he learned that he faced 142 criminal charges and the possibility of the death penalty over a deadly shooting rampage inside a Colorado movie theater.

Holmes, making his second court appearance, was formally charged with 24 counts of murder and 116 counts of attempted murder — two for each of the 12 people killed and 58 wounded. For each victim, Holmes was charged once for showing deliberation and once for showing extreme indifference to human life.

He was also charged with illegally possessing explosives, reflecting the hive of booby traps that police found inside his apartment after he was arrested outside the movie theater, just moments after the July 20 shooting.

The former graduate student sat at the defense table, flanked by his two leading public defenders. His bright orange-pink hair, an unruly frizz at his first hearing, had been combed flat to his head, and he spent much of the hearing gazing wide-eyed in front of him or staring toward the ceiling lights.

He said one word — ‘‘Yes’’ — in response to a question from Judge William B. Sylvester about setting a hearing date.

Holmes’s lawyers have declined to make any public comment, and they have not indicated in court whether they will seek an insanity defense. Under Colorado law, defendants are not legally liable for their acts if their minds are so impaired that they cannot distinguish between right and wrong.

Holmes’s public defenders could argue he is not mentally competent to stand trial. If they cannot convince the court that he is mentally incompetent, and he is convicted, they can try to stave off a possible death penalty by arguing that he is mentally ill.

Prosecutors will decide whether to seek the death penalty in the coming weeks.

Both murder charges — murder with deliberation and murder with extreme indifference — carry a maximum death penalty upon conviction; the minimum is life without parole. A conviction under extreme indifference means that any life sentences would have to be served consecutively.

The hearing, in a second-floor courtroom packed with reporters, relatives of victims, and members of the public, focused mostly on procedural issues and offered a glimpse of how slowly the complex and voluminous legal case against Holmes is likely to move in the months ahead.

It could be a year or more before a jury sits to decide whether Holmes is guilty of walking into a midnight screening of ‘‘The Dark Knight Rises’’ and opening fire on the sold-out crowd. When he was apprehended outside the Century 16 multiplex, he had four weapons and was wearing a black commando-style outfit, authorities said.

Relatives of the victims and people who survived the shooting packed the seats of the courtroom Monday. One young woman wore an oversize Batman shirt, one hand in a cast. One man walked from court limping, gauze rolled around one ankle.

Many had come to gaze for a first or a second time at Holmes, to try to glean some understanding from searching his face.

One of those in court was Maryellen Hansen, a great-aunt of the youngest person killed in the shooting, 6-year-old Veronica Moser-Sullivan. Veronica’s mother, Ashley Moser, was paralyzed in the shooting and miscarried her baby over the weekend.

The family, Hansen said, was devastated. But she decided to attend court because she wanted to see Holmes and represent her family, she said.

‘‘I felt anger, and I felt resentment that anybody could take away someone’s life for just going to the movies,’’ she said. ‘‘I also felt sorry for him. Here was a brilliant person that could’ve done a lot of good. What went wrong?’’

Unlike Holmes’s first court appearance July 23, Monday’s hearing was not televised. At the request of the defense, Sylvester barred video and still cameras from the hearing, saying that expanded coverage could interfere with Holmes’s right to a fair trial.

Last week, Sylvester allowed a live video feed that permitted the world its first glimpse of the shooting suspect.

Prosecutors and defense lawyers spent much of Monday’s hearing discussing a notebook that Holmes had sent to Dr. Lynne Fenton, his psychiatrist at the University of Colorado Denver. Holmes, who grew up in Southern California, had been a first-year neuroscience graduate student before leaving the program this spring.

Three days after the shooting, the university discovered the package from Holmes and alerted law enforcement officials, who seized it. Holmes’s lawyers have argued that the notebook contains information protected by doctor-patient confidentiality, and they have asked that it be turned over to the defense.

Sylvester did not rule on the merits of their claims Monday, and he instead set Aug. 16 as the date to hear arguments on the issue.