Spokeswoman Jacque Montgomery says 24-year-old James Holmes was studying neuroscience in a Ph.D. program at the University of Colorado-Denver graduate school. University officials earlier said he was a student at the university's medical school.
Montgomery says Holmes enrolled in the program in June 2011 and was in the process of withdrawing.
Authorities say Holmes fired into a crowded movie theater in the Denver suburb of Aurora while wearing a gas mask.
Holmes graduated from high school in the San Diego area. He's in police custody, and the FBI says there is no indication the attack is tied to any terrorist groups.