Police have confirmed 12 people have been killed and up to 50 injured after a shooting at a screening of the new Batman film in Denver, Colorado.
The suspect is now in custody, and has been named by US media as 24-year-old James Holmes.
A news press conference held by the Chief of the Aurora PD, Dan Oates, said that the shooting occurred just after 12.30am at a late night showing of the movie The Dark Knight Rises.
The suspect set off a gas canister before opening fire, and subsequently made claims to the police on the scene about explosives in his vicinity and his own residence.
His home is now being searched.
News coming out of the area states that the screening at the Aurora Mall was sold out, and the shooting broke out just after the trailers were shown.
Local reports say that some children are thought to be among the injured. The film has a PG 13 certificate in the States.
Eyewitnesses are stating that at first people thought the gunshots were part of the film.
The Dark Knight Rises, in which Batman tells Catwoman not to use guns, was released across the US today (20 July).
The cast are currently in Europe promoting the movie.
Time Warner's Warner Bros. have released the following statement: "Warner Bros. is deeply saddened to learn about this shocking incident. We extend our sincere sympathies to the families and loved ones of the victims at this tragic time."