Twelve people were killed and at least 50 others were hurt in one of the deadliest mass shootings in recent U.S. history.

The suspect was identified as 24-year-old James Holmes. A spokeswoman for the University of Colorado School of Medicine says he dropped out last month. Officials said they haven't found any links to terrorist groups.

The gunfire broke out near the start of a midnight showing of the new Batman movie, "The Dark Knight Rises." Some in the crowd thought it was a stunt at first.

One woman who was in the theater said she felt bullet casings falling on her head, burning her forehead. She said the shooter fired steadily, except when he stopped to reload.

A federal law enforcement official said the shooter had an assault rifle, a shotgun and two pistols.

Authorities are now searching Holmes' apartment, a few miles from the theater. They said they found it to be booby-trapped.

They've evacuated five buildings as they try to determine how to disarm flammable and explosive material.