CENTENNIAL, Colo. — His hair a frizz of neon orange, his hands shackled, James E. ­Holmes sat wordlessly through his first court appearance Monday, a starkly different figure from the once-promising student recalled by acquaintances or the black-clad gunman accused of striding into a theater and fatally shooting 12 people.

Sitting next to one of his publicly appointed defense lawyers, Holmes, 24, gave little outward sign of recognition as a district court judge here informed him of his rights and of the likelihood that he would face charges of first-degree murder. Prosecutors are expected to file charges formally next Monday.

The proceeding offered the first public glimpse of Holmes since he was arrested outside the Century 16 multiplex in Aurora early Friday, just minutes after the shooting.

But the hearing answered none of the questions about his state of mind, his motives, or his decline from neuroscience graduate student at the University of Colorado in Denver to the sole defendant in Colorado’s worst mass shooting in more than a decade.

Holmes has not been speaking to authorities since his arrest and is in solitary confinement on suspicion of first-
degree murder at the Arapahoe County Detention Center. He has been appointed a lawyer in the case, James O’Connor, the region’s chief public defender.

Monday’s advisement hearing before Judge William Blair Sylvester lasted about 15 minutes, and Holmes, who appeared dazed, did not speak.

Holmes appeared impassive during the hearing, staring down toward the courtroom floor, his eyes sometimes bugging out wide, sometimes nearly closed. One of his lawyers had to nudge him to stand up when the judge entered the courtroom.

A few family members of victims sat in the front rows of the second-floor courthouse, some of them staring hard at Holmes as defense lawyers and prosecutors discussed legal issues related to pretrial publicity and to granting the defense access to Holmes’s apartment and the suburban theater where the shooting occurred.

The Arapahoe County district attorney, Carol Chambers, said Holmes could face a multitude of charges. Not only were 12 people killed and 58 wounded, but the police say Holmes laid explosive booby traps in his Aurora apartment that appeared designed to kill police officers or anyone else who entered.

Prosecutors have not said whether they would seek the death penalty in the case. Chambers said investigators were still poring over ‘‘an enormous amount of evidence.’’

‘‘We would never presume that it would be slam-dunk,’’ she said. ‘‘We will work very hard on this case to prosecute it, just like we would any other case.’’

Holmes was led into court Monday in a maroon prison jumpsuit with his hands cuffed. Unshaven and appearing dazed, Holmes sat almost motionless, his eyes drooping as the judge spoke to him. At one point, Holmes simply closed his eyes.

His public defense lawyer answered all the questions posed by the judge. Prosecutors said they did not know whether Holmes was being medicated.

The televised court appearance gave millions the chance to scrutinize Holmes’s heavy eyelids and sluggish movements. The relatives of victims said they were angered by his demeanor.

Tom Teves, whose son, Alex, was killed in the attack, watched Holmes intently throughout the roughly 12-minute hearing.

‘‘I saw the coward in court today and Alex could have wiped the floor with him without breaking a sweat,’’ the Associated Press quoted Teves as saying. His son, a physical therapist, dove to protect his girlfriend during ‘‘The Dark Knight Rises’’ shooting in Aurora, a Denver suburb.

At a news conference in San Diego, where Holmes’s family lives, Lisa Damiani, a lawyer for the family, declined to answer specific questions about his relationship with his family. But, when asked, she said the family stood by him.

‘‘Yes, they do,’’ Damiani said. ‘‘He’s their son.’’

Damiani also said that their hearts go out to the victims of the shooting.

Damiani said the suspect’s mother, Arlene Holmes, received a phone call at 5:45 a.m. Friday from an ABC News reporter who asked if she was the mother of James Holmes who lives in Aurora.

Arlene Holmes said that when she told the reporter that morning, ‘‘Yes, you have the right person,’’ she was referring to the fact that she is the mother of Holmes, and not saying that she expected this to happen and knew that police had arrested the right person.

Three days after the shooting unfolded, details were still emerging about Holmes, a budding scientist who was doing graduate work at the Anschutz Medical Campus of the University of Colorado Denver before he dropped out this year, and who once received a prestigious grant from the National Institutes of Health.

Those who knew Holmes, who is from Southern California, have described him as quiet and strange, albeit talented.

The Aurora police chief, Dan Oates, has said that authorities are making progress in the case, but he has cautioned that the investigation will take time.

Police have said they believe Holmes began planning his rampage months ago, when he began acquiring the guns and ammunition he used for the shooting and also to rig his apartment with explosives. Holmes was able to purchase thousands of rounds for his weapons over the Internet.

Chambers, who has a reputation in Colorado for seeking the death penalty in murder cases, declined to say what punishment she would seek.

But David Sanchez, the father-in-law of Caleb Medley, a man wounded in the rampage, offered a more decisive opinion outside the courthouse when asked what penalty might be appropriate if Holmes was convicted: ‘‘I think death is.’’

Chambers’s office is responsible for the convictions of two of the three people on Colorado’s death row, the Associated Press reported.

Chambers also is the only state district attorney to seek the death penalty in a case in the last five years, said Michael Radelet, a sociology professor at the University of Colorado at Boulder who tracks death penalty cases.

Colorado uses the death penalty relatively sparingly. There has been only one execution since it was reinstated by the US Supreme Court in 1976. The state Legislature fell one vote short of abolishing the death penalty in 2009.

Outside the courthouse, a throng of news media members and curious onlookers gathered Monday, hoping for a glimpse of Holmes. The courtroom was packed and a room was set up to accommodate reporters who have come from around the world to cover the case.