Columbine High School massacre

Columbine High School massacre
Columbine High School massacre
	Harris (left) and Klebold (right) in the cafeteria at 11:57 a.m.
Location	39°36′12″N 105°04′29″W / 39.60333°N 105.07472°W; Columbine, Colorado, U.S.
Date	April 20, 1999 ; 11:19 a.m. – 12:08 p.m. (MDT; UTC−06:00)
Target	Students and staff at Columbine High School, first responders
Attack type	School shooting, mass shooting, mass murder, murder–suicide, arson, attempted bombing, shootout
Weapons	Harris: 9mm Hi-Point 995 carbine; 12-gauge Savage 67H pump-action shotgun (sawed-off); 2 knives (unused); Klebold: 9mm Intratec TEC-9 Mini pistol; 12-gauge Stevens 311D double-barreled shotgun (sawed-off); 2 knives (unused); Both: 48 CO; 2 cartridge bombs; 27 pipe bombs; 11 1.5-gallon propane bombs; 7 gas or napalm bombs; 4 20-pound propane bombs (including 2 car bombs); 1 25-pound propane bomb;
Deaths	16 (total, including both perpetrators and a victim who died in 2025) Harris: 9; Klebold: 5;
Injured	23 (3 indirectly; combined total) Harris: 13; Klebold: 10;
Perpetrators	Eric Harris and Dylan Klebold
Motive	See § Motive
Convicted	Mark Manes and Philip Duran (weapons suppliers)
Convictions	Manes and Duran:; Supplying a handgun to a minor, possession of an illegally sawed-off shotgun
Sentence	Manes:; 6 years imprisonment; Duran:; 4+1⁄2 years imprisonment
Litigation	Multiple lawsuits against the perpetrators' families and suppliers of the weapons

On April 20, 1999, twelfth-grade students Eric Harris and Dylan Klebold murdered 13 students and one teacher in a school shooting and attempted bombing at Columbine High School in Columbine, Colorado, United States. Their gunshots injured 20 more people; three others were injured while trying to escape. The attack ended when Harris and Klebold died by suicide. The Columbine massacre was the deadliest mass shooting at a K–12 school in U.S. history until the Sandy Hook Elementary School shooting in December 2012. It remains among the most infamous massacres in the United States and the deadliest mass shooting in Colorado. As of June 2025, it had inspired more than 70 copycat attacks, a phenomenon dubbed the Columbine effect, and Columbine has become a byword for modern school shootings.

Harris and Klebold, who planned for roughly a year, intended the attack to be primarily a bombing and only secondarily a shooting. The pair launched a shooting attack after the homemade bombs they planted in the school failed to detonate. Their motive remains uncertain. The police were slow to enter the school and were heavily criticized for not intervening during the shooting. The incident resulted in the introduction of the immediate action rapid deployment (IARD) tactic, which is used in active-shooter situations, and an increased emphasis on school security with zero-tolerance policies. The violence sparked debates over American gun culture and gun control laws, high school cliques, subcultures (e.g. goths), outcasts, and school bullying, as well as teenage use of pharmaceutical antidepressants, the Internet, and violence in video games and film.

Many makeshift memorials were created after the massacre, including ones using victim Rachel Scott's car and John Tomlin's truck. Fifteen crosses for the victims and the shooters were erected on top of a hill in Clement Park. The crosses for Harris and Klebold were later removed after controversy. The planning for a permanent memorial began in June 1999, and the resulting Columbine Memorial opened to the public in September 2007.