University of Colorado officials disclosed Monday that mass shooting suspect James Holmes was being paid $26,000 a year for his studies, money that could have financed the cache of firearms, ammunition and explosive devices found in his apartment.

Holmes, 24, unexpectedly dropped out of an elite neuroscience graduate program June 10 after failing part of his first-year final exam.

School officials say they were stunned to learn of his arrest Friday after a shooting rampage at a packed movie house a few miles from campus that left 12 dead and 58 wounded. Police found Holmes' apartment near campus filled with booby-trapped explosive devices.

At an initial court appearance Monday morning, Holmes had orange hair and a dazed demeanor, a contrast to the doctoral candidate who arrived at the university with stellar academic credentials and references. He's due back in court July 30, when he is expected to face several first-degree murder charges.

"Everybody is in a state of shock," graduate school Dean Barry Shur said. "Everybody is upset. Who wouldn't be?"

The program to which Holmes was accepted last fall admits just six students a year. Candidates have top grades and "near perfect" test scores, Shur said. They undergo a background check but no mental examination. "No program requires psychiatric evaluation, to the best of my knowledge,"

Holmes came with "excellent academic credentials," Shur said at a press briefing Monday flanked by school Chancellor Don Elliman and Executive Vice Chancellor Lilly Marks.

Shure and other administrators were at a loss to explain Holmes' motive, especially given Shur's comments that the faculty "tightly monitors" its neuroscience students.

Doctoral students receive free tuition, and most get federally sponsored 12-month grants of $26,000, about $500 a week. Holmes, who was not employed, bought an assault rifle, shotgun, two semi-automatic handguns and 6,000 rounds of ammunition in the months leading up to what police called a methodically planned shooting spree.

Officials say virtually no doctoral student has an outside job, given the intense nature of the program, which can take four or more years to complete.

Holmes has been described as a shy, quiet loner. Shur did not characterize him, but said scientists often immerse themselves in academics and research. "Scientists are quirky people," he said. "There are a lot of intense characters."

The preliminary exam, given orally by three professors, is designed to determine a student's basic knowledge and possible weaknesses, not weed anyone out, the officials said. The school would have provided remedial work and retesting if Holmes had sought help, Shur said. But after apparently failing June 7, he dropped out three days later. Campus Police Chief Doug Abraham said Holmes' school identification cards, which provide access to its facilities, were voided June 12.

School officials would not say if faculty contacted Holmes after his departure, but Shur said he never received forms from Holmes with an explanation for dropping out. "My understanding is he partially completed the forms but did not fill in his reason for leaving the program," Shur said.

School officials repeatedly deflected questions about Holmes' academic performance and details after he dropped out June 10, citing the ongoing criminal investigation into the case, but acknowledged it was unusual to quit.

Over the weeks before Holmes left, 90 packages containing ammunition and other items were shipped to the campus. Elliman said there was no way of knowing the volume or content of the shipments, which went directly to Holmes or to a campus mailroom. "We have thousands of packages that come here every day," he said.

The suburban Denver campus was on alert Monday, when a suspicious package was found at a professor's office and a second in a campus mailroom, school spokesman Daniel Meyers said. Both buildings were locked down but later reopened.

Authorities are checking whether materials from campus labs were used in the explosive devices found in Holmes' apartment.