By Pete Williams and NBC News staff

The man suspected of carrying out the Colorado movie theater shooting, 24-year-old James Holmes from San Diego, was a graduate student in the neuroscience program at the University of Colorado Medical School, a university spokesman told NBC News. He was in the process of withdrawing from school, the university confirmed.

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James Holmes, the suspect in the Aurora, Colo. movie theater shooting.

“The University of Colorado Denver Anschutz Medical Campus can confirm that Mr. James Holmes was in the process of withdrawing from the University of Colorado Denver’s graduate program in neurosciences,” the univesity statement said. “Mr. Holmes enrolled at the university in June 2011.”

The university website listed one of his courses as the Biological Basis of Psychiatric and Neurological Disorders. He was listed on the class website as making apresentation in the spring on MicroRNA biomarkers.

Officials said they believe Holmes, born Dec. 13, 1987,  is the man who killed at least 12 people at a midnight showing of the new Batman movie in Aurora, a suburb of Denver. He will be arraigned in court on Monday. News organizations have made requests to the judge to allow cameras in the courtroom.

Know James Holmes? If you have information, send an email to Bill Dedman of NBC News.

Holmes’ family, who live in Rancho Penasquitos, a community in the northeastern part of San Diego, issued a statement through the San Diego Police Department. They said “Our hearts go out to those who were involved in this tragedy and to the family and friends of those involved. We ask that the media respect our privacy during this difficult time. Our family is cooperating with authorities in San Diego, California, and Aurora, Colorado. We are still trying to process this information and we appreciate that people will respect our privacy.” A man believed to be Holmes’ father was seen leaving with luggage, escorted by police.

Police said he had attended a San Diego High School, but did not say which one.

Public records give a previous address in Riverside, Calif., including a dormitory at University of California Riverside. There is no mention  of Holmes on the university website.

Public records indicate that Holmes lived with two roommates, also from California, in the Aurora building where police have found explosives, at 1690 Paris St., Apt. 10. The building is reserved for students, faculty and staff from the medical campus.

The Denver Post newspaper reported that Holmes, in an apartment rental application he last year, described himself as “quiet and easy-going.” A pharmacy student who lives in the building told The Post he called 911 around 12:30 a.m. because there was a song blaring from the stereo inside apartment 10, where Holmes lived. The student, who wanted to be identified only as Ben, said he couldn’t make out the song but that it seemed to be the same one playing on repeat. He also said Holmes kept to himself and wouldn’t acknowledge people when they passed in the hall and said hello.”No one knew him. No one,” he told The Post.

Holmes was not on any watch list that would have alerted authorities that he was dangerous, officials said. The incident was not believed to have any connection to international terrorism, they added.

An earlier report that the car Holmes was driving had Tennessee plates turned out to be incorrect, officials said.

Federal officials said the shooter brought four weapons to the theater:

• Two were handguns, made by Glock. One was a 40-caliber. The size of the other wasn’t specified.
• One shotgun, a Remington model 870, one of the most popular models. Pump action, single barrel.
• And one Smith and Wesson AR-15 type rifle, called by some an “assault rifle.”  hese weapons can accommodate large ammunition “clips,” but authorities have not yet said what kind of magazines were at the scene.

The purchase place and dates are still being traced.

Police said the gunman entered through an exit door and appeared at the front of the theater in Aurora, Colo., and released a canister, thought to be tear gas, that let out a hissing sound.

He then started shooting into the crowd, sparking pandemonium.  Police told NBC News that Holmes carried two pistols, a rifle and a shotgun.

Witnesses said he was wearing a bullet-proof vest and dressed entirely in black. Some also said he was wearing a gas mask or goggles. A police officer told TODAY that the shooter might have been wearing “some sort of Batman costume.”

“He looked so calm when he did it,” an eyewitness told NBC affiliate KUSA. “It was like scary. He waited for both the bombs to explode before he did anything. Then, after both of them exploded, he began to shoot.”

“He had no specific target. He just started letting loose,” the witness added.

Witnesses told reporters that the gunfire erupted during a shootout scene in the “The Dark Knight Rises.”

“I have heard he was possibly wearing some sort of Batman costume,” police spokesman Frank Fania told TODAY.

Holmes was later detained in the movie theater parking lot. He was carrying a knife, a rifle and a handgun.

“He did not resist, he did not put up a fight,” Fania told Reuters.

He also said it appeared the shooter did not have any accomplices.

“We’re pretty confident he acted alone,” Fania said.

After being captured by police, Holmes told authorities he had explosive materials in his apartment, KUSA reported.

Local and federal officials searched Holmes’ apartment building, which was evacuated soon after the shooting, sources told NBC News.

Aurora Police Chief Dan Oates said it was established that the apartment had been booby-trapped with sophisticated explosives or flammable material and officers were trying to determine how to defuse the device or devices.

Fania told TODAY that Holmes had been given a “minor” traffic ticket in 2011.

Holmes was scheduled to appear in court to face charges on Monday afternoon, KUSA reported.

The Associated Press and Reuters contributed to this report.

Source: usnews.msnbc.msn.com