Twelve civilians in an Aurora, Colorado movie theater were killed late last night during an attack during the midnight premiere of The Dark Knight Rises.

The assailant, now confirmed as 24-year-old Aurora resident James Eagan Holmes, sported a gas mask and bullet-proof vest according to sources during the assault. Holmes was detained by Colorado police, who arrived at the scene nearly a minute after the events had begun, according to Aurora Police Chief Dan Oates.

Police arrested Holmes behind the theater, who found four weapons in his possession. The weapons included two .40-caliber Glock handguns, an 870 Remington shotgun, and an AR-15 assault rifle. Holmes had also used smoke devices to distract the crowd during the shooting.

Holmes did not resist arrest. According to reports, he was sporting all-black attire as well as dyed red hair. Suspicions Holmes was delusional and identified strongly with the Joker character from the Batman series were confirmed as ABC News reports that at the time of his arrest, Holmes told police, “I am the Joker.”

Police invaded Holmes’ apartment, which Aurora Deputy Fire Chief Chris Henderson revealed to be laced with “sophisticated” booby traps, making it more difficult for officials to investigate.

Holmes was a graduate student at the University of Colorado school of medicine studying neuroscience, according to The AP. He had dropped out of courses only a few weeks before to last night’s events.

Friends and family routinely identified Holmes as a “quiet” type, but never suspected any problems of this magnitude. His former neighbor Tom Mai, who had lived next to the family for several years in San Diego, California, describes James as a “typical American kid,” according to The North County Times.

The incident prompted the film’s production company Warner Bros. to close its Paris premiere, where the cast and crew were in attendance. Director Christopher Nolan, along with actors Christian Bale, Anne Hathaway, and Morgan Freeman were also slated to hold a press conference this morning, which was cancelled as well.

Warner Bros. issued a statement after the tragedy, saying, “We extend our sincere sympathies to the families and loved ones of the victims at this tragic time.”

U.S. President Barack Obama temporarily suspending campaigning for the fall elections due to the incident. He was in Fort Myers, Florida for a previously scheduled event, which was halted before his abrupt return to Washington D.C.

“Our time here is limited and it is precious,” the president said in Fort Myers. “And what matters at the end of the day is not the small things, it’s not the trivial things, which so often consume us and our daily lives.  Ultimately, it’s how we choose to treat one another and how we love one another.”

Ten of the victims died immediately at the scene, while two others were reported dead after being rushed to a hospital. In all, Holmes had either killed or wounded 71 civilians in the theater.

No reports indicate that Holmes was connected to any outside terrorist forces.