AURORA, Colo. (AP) -- We are learning more about the suspected gunman accused of killing a dozen people when he fired into a crowded movie theater in the Denver suburb of Aurora.
James Holmes, the suspect in a mass shooting at a Colorado movie theater dropped out of medical school last month.
Spokeswoman Jacque Montgomery says 24-year-old James Holmes was a student at the University of Colorado School of Medicine in Denver until last month. She did not know when he started school or why he withdrew.
New York City's police commissioner says the gunman in the Colorado movie theater rampage had painted his hair red and called himself the Joker -- the villain from the Batman movies.
Police Commissioner Raymond Kelly said Friday that he had been briefed about the shootings that killed 12 and wounded nearly 60 others at a showing of the new Batman movie "The Dark Knight Rises" at a suburban Denver theater.
Kelly and his spokesman did not say who briefed him.
Aurora Police Chief Dan Oates would not confirm the information about suspected gunman James Holmes, but confirmed he had spoken to Kelly. The two used to work together in New York.
Holmes is in police custody, and the FBI says there is no indication the attack is tied to any terrorist groups.
A law enforcement official briefed on the investigation told The Associated Press that 24-year-old James Holmes is reportedly not talking to investigators.
The official spoke on condition of anonymity to discuss the ongoing case.
A police chief says a Colorado shooting suspect's apartment is posing a "vexing problem" as officers face challenges in safely entering the residence where booby traps were set.
Colorado firefighters are monitoring the Aurora apartment building for gases in an effort to determine what chemicals they say 24-year-old James Holmes might have used to trap the place.
Holmes is the suspect in a mass shooting Friday at a midnight screening of "The Dark Knight Rises." Twelve people were killed in the attack and dozens were injured.
Aurora Police Chief Dan Oates said photos of Holmes' apartment appeared to show trip wires, jars full of ammunition and liquid and other items unlike anything the chief has ever seen.
Police on Friday evening escorted residents seeking to gather personal items into several apartment buildings in the area that were evacuated.