BY NICHOLAS RICCARDI and GILLIAN FLACCUS

Associated Press

AURORA, Colo. — University of Colorado officials were looking Sunday into whether James Holmes used his position in a graduate program to collect hazardous materials, but school officials weren’t saying whether they knew the suspect in a movie theater massacre was anything more than a hard-working student.

Law enforcement officials also revealed that Holmes, 24, has not been cooperating with them and that it could take months to learn what prompted the attack early Friday on a packed theater of moviegoers watching the premiere of the latest Batman movie. The assault killed 12 and left 58 wounded.

Investigators found a Batman mask inside Holmes’ apartment after they finished clearing the home of booby traps and ammunition, a law enforcement official close to the investigation said Sunday on condition of anonymity because he was not authorized to speak to the press.

Meanwhile, President Barack Obama flew to Colorado for a few hours to comfort residents in a state that’s critical to the November election. He began his visit with the family members of the victims at the University of Colorado Hospital, which treated 23 of the people injured; 10 remain there, seven hurt critically. The hospital is a short drive from the site of the shooting.

After meeting with the families, he said that he was there “not as president but as a father and a husband.”

He said that “we can all understand what it would be to have someone taken from us in this fashion.”

Holmes was being held in solitary confinement at a Denver-area county detention facility, Aurora Police Chief Dan Oates said, and is “lawyered up.”

“He’s not talking to us,” the chief said. He is scheduled for an initial hearing Monday at 9:30 a.m. MDT, and has been assigned a public defender.

Police have said that Holmes began buying guns at Denver-area stores nearly two months before Friday’s shooting and that he received at least 50 packages in four months at his home and at school. Also on Sunday, a gun range owner east of Denver said he recently rejected a membership application from Holmes in part because of a bizarre voice mail greeting on Holmes’ phone.

While the University of Colorado disclosed that it was cooperating with police in the case, that disclosure was one of the few the university has made three days after the massacre. It remained unclear whether Holmes’ professors and other students at his 35-student Ph.D. program noticed anything unusual about his behavior.

His reasons for quitting the program in June, just a year into the five- to seven-year program, also remained a mystery.

Holmes recently took an intense, three-part oral exam that marks the end of the first year. Those who do well continue with their studies and shift to full-time research, while those who don’t do well meet with advisers and discuss their options, including retaking the exam. University officials would not say if he passed, citing privacy concerns.

The university said Holmes gave no reason for his withdrawal, a decision he made in June.

Holmes was not allowed access from the institution after his withdrawal, which was “standard operating procedure” because he was no longer affiliated with the school, Montgomery said. Holmes had no contact with university police, she said.

The university declined to release any details of his academic record, citing privacy concerns, and at least two dozen professors and other staff declined to speak with The Associated Press. Some said they were instructed not to talk publicly about Holmes in a blanket email sent to university employees.

Jacque Montgomery, a spokeswoman for the University of Colorado medical school, said that police have told the school to not talk about Holmes. The university also took down the website for its graduate neuroscience program on Saturday.

Dan Keeney, president of DPK Public Relations in Dallas, said asking for silence from university employees because of a police investigation was appropriate, but taking down the website was “indefensible” for a publicly funded university unless the school believed it contained inaccurate information relating to the program.

“It’s an indefensible action,” he said. “It’s disappointing to hear that they would take that action because it suggests that it’s not in the public’s interest to have access to that information and I think it is in the public’s interest.”

Amid the continuing investigation of Holmes and his background, Sunday was a day for healing and remembrance in Aurora, with Congregations across Colorado prayed for the shooting victims and their relatives. Churches sent out social-media appeals for neighbors who wanted to join in remembrance. Elderly churchgoers at an aging Presbyterian church within walking distance near Holmes’ apartment joined in prayer, though none had ever met him.

Hundreds gathered for prayers and healing at the vigil Sunday night, where a banner said, “Angels Walk With Those Who grieve.

“You’re not alone, and you will get through it,” said the Rev. Kenneth Berve, pastor at Grant Avenue United Methodist Church and a witness to Friday’s horrors. “We can’t let fear and anger take control of us.”

Aurora resident Heather Lebedoff, 24, placed a rose on each cross that had been erected in memory of those killed. She said she didn’t know anyone in the theater, but she felt connected to her neighbors and all the pain they have gone through.

“This is the city I live in, and I know there are a lot of people affected by this. Stuff like this really shows what love and community is all about.”

Meanwhile, the owner of a gun range told the AP that Holmes applied to join the club last month but never became a member because of his behavior and a “bizarre” message on his voice mail.

He emailed an application to join the Lead Valley Range in Byers on June 25 in which he said he was not a user of illegal drugs or a convicted felon, said owner Glenn Rotkovich. When Rotkovich called to invite him to a mandatory orientation the following week, he said he heard a message on Holmes’ voice mail that was “bizarre — guttural, freakish at best.”

He left two other messages but eventually told his staff to watch out for Holmes at the July 1 orientation and not to accept him into the club, Rotkovich said.

The shooting was the worst in the U.S. since the Nov. 5, 2009, attack at Fort Hood, Texas. An Army psychiatrist was charged with killing 13 soldiers and civilians and wounding more than two dozen others.