On July 20, 2012, a mass shooting occurred inside a Century 16 movie theater in Aurora, Colorado, United States, during a midnight screening of the film The Dark Knight Rises. Dressed in tactical clothing, James Holmes set off tear gas grenades and shot into the audience with multiple firearms. Twelve people were killed and 70 others were injured, 58 of them from gunfire. It was the deadliest shooting in Colorado since the Columbine High School massacre in 1999. At the time, the event had the largest number of victims (82) in one shooting in modern U.S. history. This number was eventually surpassed by the 107 victims in the 2016 Orlando nightclub shooting.

Holmes was arrested minutes later in his car outside the cinema. Earlier, he had rigged his apartment with homemade explosives and incendiary devices. These were defused by the Arapahoe County Sheriff's Office Bomb Squad a day after the shooting.

Fearing copycat crimes, movie theaters showing the same film across the US increased their security. Gun sales increased in Colorado, and political debates were generated about gun control in the United States.

Holmes confessed to the shooting but pleaded not guilty by reason of insanity. Arapahoe County prosecutors sought the death penalty. The trial began on April 27, 2015. On July 16 of that year, Holmes was convicted of 24 counts of first-degree murder, 140 counts of attempted first-degree murder, and one count of possessing explosives. On August 7, the jury deadlocked on whether to impose the death penalty. On August 26, Holmes was given 12 life sentences, one for every person he killed; he also received 3,318 years for the attempted murders of those he wounded and for rigging his apartment with explosives.

James Eagan Holmes (born December 13, 1987) is an American mass murderer responsible for the 2012 Aurora, Colorado shooting in which he killed 12 people and injured 70 others (62 directly and eight indirectly) at a Century 16 movie theater on July 20, 2012. He had no known criminal background before the shooting occurred. Before the shooting, Holmes booby-trapped his apartment with explosives, which were defused one day later by a bomb squad.

Holmes was arrested shortly after the shooting and was jailed without bail while awaiting trial. Following this, he was hospitalized after attempting suicide several times while in jail. Holmes entered a plea of not guilty by reason of insanity, which was accepted. His trial began on April 27, 2015, and on August 24 he was sentenced to 12 consecutive life sentences plus 3,318 years without parole.