A dozen people were killed and around 59 were injured in Aurora, near Denver, Colorado when attending a midnight showing of the new Batman film, The Dark Knight Rises. One of the suspects, a 25-year-old man, has been taken into custody.
The movie theater was packed for the midnight premiere of the new movie and many of those present were young fans.
The youngest victim reported was a 6-year-old being treated at Children's Hospital Colorado, as media reports note.
According to witnesses, the violence erupted around 15 minutes into the movie. Some witnesses say they thought it was some new type of special effect in the theater.
Local media are reporting two gunmen were involved in the shooting rampage and that an explosive device was also set off during the shooting, which injured several people.
Witnesses said the gunmen appeared to be wearing body armor and gas masks, and that they used a tear gas bomb in the attack.
FBI agents and police officers from all local jurisdictions were on the scene, prompting fears the incident was related to a terrorist attack. Police are searching for a possible second bomb on the premises.
Various media reports indicate one suspect is in custody and a manhunt is underway for a second suspect. NBC News identifies one of the suspects as James E. Holmes, born 1987. He reportedly had Tennessee license plates on the vehicle he was driving at the time of the shooting, but a connection to that state remains unclear, the Huffington Post notes.
CNN confirms he'll appear in court on Monday.
Reuters posted a photo of Holmes here.
The living room of the suspect's apartment was crisscrossed with trip wires connected to what appeared to be plastic bottles containing an unknown liquid, said Chris Henderson, Aurora's deputy fire chief. There are plans to detonate the suspected explosives with a robot, he said.
A timeline on reddit provides a comprehensive look into what occurred and which hospitals are treating the victims.
Nicole Williams, at the nearby Swedish Medical Centre told 9News the hospital was notified of a "mass casualty incident" at 1.15am.
As Digital Journalist Darren Weir reports, a Colorado resident who narrowly missed being in the line of fire during Toronto's Eaton Centre shooting was among the casualties.
New York Police confirmed they will beef up security "where the 'The Dark Knight Rises' is playing in the five boroughs."
President Obama cancelled a campaign event in Fort Myers, Florida to speak on the shooting. Obama said, "Such violence, such evil is senseless...If there's anything to take away from this tragedy it's the reminder that life is very fragile."
Latest update: It has now been reported that 12 were killed and 38 were wounded in the incident, and that only one suspect was involved in the shooting.