CENTENNIAL, Colo. — The suspect in the Colorado movie theater killings returns to court this week for a hearing that might be the closest thing to a trial the victims and their families will get to see.

 James Holmes, a former neuroscience graduate student, is charged with killing 12 people and injuring 70 by opening fire in a darkened theater in the Denver suburb of Aurora last July.

 At a weeklong preliminary hearing starting Monday, prosecutors will outline their case against Holmes, the first official public disclosure of their evidence. The judge will then determine whether to send the case to trial.

 Legal analysts say that evidence appears to be so strong that Holmes may well accept a plea agreement before trial. In such cases, the preliminary hearing can set the stage for a deal by letting each side assess the other’s strengths and weaknesses, said Laurie Levenson, a former federal prosecutor and now a professor at Loyola Law School in Los Angeles.

 Preliminary hearings “are often the first step to resolving the case, a mini-trial so both sides can see the writing on the wall,” Levenson said.

 Judges rarely throw out a case at this stage because prosecutors must only meet a “probable cause” standard — much lower than the “beyond a reasonable doubt” standard for a guilty verdict at trial, said Mimi Wesson, a professor of law at the University of Colorado Law School.

 Holmes, who faces more than 160 counts including first-degree murder and attempted murder, could have waived his right to a preliminary hearing, allowing lawyers on both sides to prepare for trial. But defense lawyers sometimes go through with the hearing because it gives them a clearer picture of prosecution evidence.

 “In this case, I think it likely that the genuine purpose of the hearing would be information-gathering by the defense,” Wesson said.

 Court officials expect many survivors and family members of the dead to attend the preliminary hearing, along with scores of spectators and reporters. At least two overflow rooms are being prepared where the hearing can be observed by video and audio feeds.

 District Judge William B. Sylvester has imposed a gag order on attorneys and investigators, and many court documents have been filed under seal, so little is known about Holmes’ path from promising graduate student to suspect in a mass murder.

 The few details that have been made public suggest a disturbing descent.

 Holmes enrolled in the University of Colorado, Denver Ph.D. program in neuroscience in 2011. In the spring of 2012, authorities say, he began buying weapons, high-capacity magazines, ammunition, explosives and combat gear.

At some point in the school year, he began seeing a university psychiatrist. He failed an oral exam on June 7 and withdrew from the university three days later.

 He was arrested outside the theater shortly after the July 20 shootings. Federal authorities have said he entered the theater with a ticket and is believed to have propped open a door, slipped out to his car and returned with his weapons.

 Hours later, investigators found his apartment booby-trapped with potentially deadly explosives, police said.

 In previous hearings — many witnessed by victims and survivors — Holmes’ appearance and behavior ranged from bizarre to unremarkable. On his first day in court, his hair was a shocking orange-red, his face was covered with stubble and he seemed to be in a daze.

 By last week, his hair was a natural-looking brown and he wore a full beard. He sat quietly and seemed to be aware of the proceedings.

 Holmes could get the death penalty or life in prison without parole if he goes to trial and is convicted of murder.

He could avoid the death penalty if his lawyers argue he is mentally ill or innocent by reason of insanity.

 Holmes’ mental health is expected to be a major factor whether his case ends in a plea agreement or goes to trial.

 His lawyers have told the judge that Holmes was mentally ill, and court records indicate they may call witnesses in the preliminary hearing to testify about his mental health. The defense team has not said whether Holmes would enter an insanity plea.

 An insanity plea is different from the competency argument used for Jared Loughner, who pleaded guilty to killing six people and wounding 13, including then-Rep. Gabrielle Giffords, in Arizona in 2011.

 A judge ruled in May 2011 that Loughner was mentally incompetent to stand trial and ordered him to undergo psychiatric treatment.

After Loughner spent more than a year in treatment, the judge ruled he had become competent, and Loughner accepted a plea agreement that carried a sentence of life in prison without parole instead of execution.

 The decision on whether to seek the death penalty will be up to the new district attorney for Arapahoe County, George Brauchler, who was elected in November and takes office Tuesday, after the preliminary hearing begins. Brauchler has not indicated what he will do.

 A spokeswoman for outgoing District Attorney Carol Chambers, who oversaw the filing of charges against Holmes, declined to comment.

 If prosecutors do not seek the death penalty, and if Holmes is convicted of or pleads guilty to first-degree murder charges, he would face a mandatory sentence of life without parole.