12 people were killed and around 40 wounded when a gunman opened fire Friday at a movie theater showing the latest Batman film, police said.
The police department in the town of Aurora, Colorado, where the shooting took place, said in a statement that there were "approximately 50 victims with at least 12 confirmed dead."
Police had earlier put the toll in the shooting at the Century 16 Movie Theater, which was holding a midnight showing of "The Dark Knight Rises," at 14 dead with around 50 wounded.
Witnesses told police the gunman had thrown "some type of gas or explosive device" and opened fire on moviegoers.
"When the suspect was arrested, police recovered one rifle, one handgun and a gas mask," Aurora police said. "A third gun is still inside the theater."
US television networks identified the gunman as James Holmes, a 24-year-old Aurora resident, and quoted the FBI as saying he had no known connections to terrorism.
Police said the suspect "offered no resistance when he was arrested."
"At this time, the police have no evidence that any additional suspects were involved other than the person arrested," the Aurora police said.