Columbine effect

The Columbine effect is the legacy and impact of the Columbine High School massacre, which occurred on April 20, 1999, at Columbine High School in Columbine, Colorado. The shooting has had an effect on school safety, policing tactics, prevention methods (including gun control and metal detectors), and inspired numerous copycat crimes, with many killers taking their inspiration from Eric Harris and Dylan Klebold by describing the two perpetrators as being martyrs or heroes.

The shooting has also had a significant impact on popular culture, with Harris and Klebold often seen and mentioned in several forms of media. Media stories often reference Harris, Klebold and the massacre whenever another school shooting occurs.

The impact of the Columbine High School shooting is felt not only in terms of school safety and popular culture, but it also raises worries about student rights violations and excessive use of force in law enforcement methods. The event demands a reevaluation of mental health advocacy and intervention tactics to avoid situations where a person becomes dangerous to themselves or others. All these different results show how the Columbine effect greatly influences society.

Background

Main article: Columbine High School massacre

Further information: Eric Harris and Dylan Klebold

On April 20, 1999, Columbine High School seniors Eric Harris and Dylan Klebold murdered 12 students and one teacher and injured 24 others. Around 50 minutes after the shooting began, Harris and Klebold took their own lives in the library, where the majority of their victims died. At the time, it was the deadliest shooting at a high school in American history. The shooting was the most covered news story of 1999, and third most followed by the American public of the entire decade, surpassing the death of John F. Kennedy Jr and the Kosovo War.

Effects on schools

Following the Columbine shooting, schools across the United States instituted new security measures such as transparent backpacks, metal detectors, school uniforms, and security guards. Some schools implemented the numbering of school doors to improve public safety response. Several schools throughout the country resorted to requiring students to wear computer-generated IDs.

Schools also adopted a zero-tolerance approach to possession of weapons and threatening behavior by students. Several social science experts feel the zero-tolerance approach adopted in schools has been implemented too harshly, however, with unintended consequences creating other problems.

In addition to this, the shooting also affected student speech rights. School officials became more concerned about student expression, mainly if it was violent or threatening, which put students' First Amendment rights at risk. There have been legal battles over students' rights to free expression, as different judges have had varying interpretations of what constitutes a genuine threat and how much discretion school officials should have in regulating student speech. This has made it a complex issue for schools and courts to balance safety and freedom of expression.

Police tactics

Police departments have reassessed their tactics and have since trained for Columbine-like situations after criticism over the slow response and progress of the SWAT teams during the shooting. First responders face numerous challenges when entering situations like this. In a similar incident, a Police Department had to deal with over 1500 misleading calls to the dispatch center during the first two hours of the incident, which underscores the difficulties that law enforcement officials face in managing misinformation distractions during active shooter incidents.

Training has been increased and now includes quick deployment rules while schools are rethinking emergency policies. The Pacifica CA Police Department has created a tactical playbook that gives planning and equips responders with strategic direction for coordinating responses between agencies when facing mass violence.

Police followed a traditional tactic at Columbine: surround the building, set up a perimeter, and contain the damage. That approach has been replaced by a tactic known as the Immediate Action Rapid Deployment tactic. This tactic calls for a team to advance into the site of any ongoing shooting, but even with just a single officer if more are not available. In fact, the majority of active shooters are stopped by a single officer. Police officers using this tactic are trained to move toward the sound of gunfire in formation and neutralize the shooter as quickly as possible. There has been widespread adoption of high-strength body armor and patrol rifles by police departments across the United States in response to the increased active shooter threat. Their goal is to stop the shooter at all costs; they are to walk past wounded victims, as the aim is to prevent the shooter from killing or wounding more. Dave Cullen has stated: "The active protocol has proved successful at numerous shootings...At Virginia Tech alone, it probably saved dozens of lives."

The Russian Prosecutor General's Office actively sought to deter incitement to commit such copycat attacks. On 2 February 2022, with immediate effect, the Supreme Court declared the "Columbine" movement as a terrorist group. Whilst the motivation for the ruling is unknown, sentencing for terrorist activity is punishable by life imprisonment in Russia.

Influence on other shootings

The Columbine shootings influenced subsequent school shootings, with several such plots mentioning it. Fear of copycats has sometimes led to the closing of entire school districts. According to psychiatrist Edwin Fuller Torrey of the Treatment Advocacy Center, a legacy of the Columbine shootings is its "allure to disaffected youth." Ralph Larkin examined twelve major school shootings in the US in the following eight years and found that in eight of those, "the shooters made explicit reference to Harris and Klebold."

A 2015 investigation by CNN identified "more than 40 people...charged with Columbine-style plots." A 2014 investigation by ABC News identified "at least 17 attacks and another 36 alleged plots or serious threats against schools since the assault on Columbine High School that can be tied to the 1999 massacre." Ties identified by ABC News included online research by the perpetrators into the Columbine shooting, clipping news coverage and images of Columbine, explicit statements of admiration of Harris and Klebold, such as writings in journals and on social media, in video posts, and in police interviews, timing planned to an anniversary of Columbine, plans to exceed the Columbine victim counts, and other ties.

In 2015, journalist Malcolm Gladwell writing in The New Yorker magazine proposed a threshold model of school shootings in which Harris and Klebold were the triggering actors in "a slow-motion, ever-evolving riot, in which each new participant's action makes sense in reaction to and in combination with those who came before."

FBI former profiler Mary Ellen O'Toole said on CNN during the 20th anniversary of the massacre in 2019, and during the manhunt of Florida teenager Sol Pais, that she opposed the release of the Basement Tapes because of the call made by Eric Harris to other would-be shooters to "join him in infamy". She also highlighted that it was most likely males to be obsessed by the shooting and that the case of Sol Pais was rare due to her being a female.

The Treatment Advocacy Center was set up in 1998 by Dr. Fuller. This Center's primary goal is to push for changes that cover all aspects of treatment for severe mental illness (SMI), primarily legal obstacles in getting this type of care, so that people with SMI get the backing and treatment they require to flourish.

Assisted Outpatient Treatment (AOT). AOT is a method of giving mental health services in the community under civil court commitment. The AOT programs prioritize ensuring people stick with treatments and keeping safety within communities while offering a planned approach to support those with SMI.

Copycats

The first copycat may have been the W. R. Myers High School shooting, just eight days after Columbine, when a 14-year-old Canadian student went into his former school in Taber, Alberta at lunchtime with a sawed off .22 rifle under his dark blue trench coat, and opened fire, killing one student. A month after the massacre, Heritage High School in Conyers, Georgia, had a shooting which Attorney General Janet Reno called a Columbine "copycat". A friend of Harris and Klebold, Eric Veik, was arrested after threatening to "finish the job" at Columbine High School in October 1999.

Another case was in Germany in 2002. The expelled student Robert Steinhäuser involved was seeking payback against teachers, like the Columbine shooters. In Germany again, at the Amadon School, the shooter admired Eric Harris in his diary.

Another example is the Jokela High School shooting in Finland in 2007. The perpetrator, Pekka-Eric Auvinen, wore a T-shirt with a message like the one by Klebold and Harris at Columbine, reading "Humanity is Overrated". These cases show how Columbine's ideas led to other attacks.

In 2001, Charles Andrew Williams, the perpetrator of the Santana High School shooting, reportedly told his friends that he was going to "pull a Columbine," though none of them took him seriously. In 2005, Jeff Weise, who also wore a trench coat, killed his grandfather, who was a police officer, and his girlfriend. He took his grandfather's weapon and his squad car, and drove to his former high school in Red Lake and murdered several students before killing himself. In an apparent reference to Columbine, he asked one student if they believed in God.

The perpetrator of the Dawson College shooting wrote a note praising Harris and Klebold. Convicted students Brian Draper and Torey Adamcik of Pocatello High School in Idaho, who murdered their classmate Cassie Jo Stoddart, mentioned Harris and Klebold in their homemade videos, and were reportedly planning a "Columbine-like" shooting. The perpetrator of the Emsdetten school shooting praised Harris in his diary.

In September 2006, a student at East High School in Green Bay, Wisconsin informed school staff of a plot to carry out a "Columbine Style" attack on the school. A search of the involved students' homes yielded weapons and improvised explosives. Two students served time in prison for conspiracy to commit first-degree intentional homicide. A third student was given a lesser sentence for conspiracy to damage property with explosives.

In a self-made video recording sent to the news media by Seung-Hui Cho prior to his committing the Virginia Tech shootings, he referred to the Columbine massacre as an apparent motivation. In the recording, he wore a backwards baseball cap and referred to Harris and Klebold as "martyrs."

Adam Lanza, the perpetrator of the 2012 Sandy Hook Elementary School shooting, had "an obsession with mass murders, in particular, the April 1999 shootings at Columbine High School in Colorado."

In 2011, Tristan van der Vlis shot and killed six people in a shopping mall in Alphen aan den Rijn in the Netherlands before committing suicide. He was obsessed with the Columbine shootings. The date he chose for his attack was April 9, which was the birthday of Eric Harris, and he started shooting at 12:08 pm, the time when Harris committed suicide.

In June 2014, a married couple, Jerad and Amanda Miller, shot and killed two Las Vegas police officers and an intervening civilian before being confronted by police. Jerad Miller was fatally shot by an officer while Amanda Miller committed suicide shortly afterwards. They both talked about committing "the next Columbine" and idolized Harris and Klebold according to a neighbor's account.

The Tumblr fandom gained widespread media attention in February 2015 after three of its members conspired to commit a mass shooting at a Halifax mall on Valentine's Day. In 2017, two 15-year-old school boys from Northallerton, England, were charged with conspiracy to murder after becoming infatuated with the crime and "hero-worshipping" Harris and Klebold.

The Kerch Polytechnic College massacre appears to be a copycat crime. The shooter wore a white shirt which said "Hatred" (in Russian), one fingerless glove, planted bombs, and committed suicide with a shotgun in the library, all very similar to Harris' outfit and suicide.

In September 2021, two teens were arrested in Lee County, Florida, and were accused of plotting a school shooting. A search conducted of the teen's homes showed a map of the school with security cameras labeled. Several knives and a gun were also found. The Sheriff Department said the teens had a "particular interest in Columbine" and that they had been ordered to undergo mental evaluation before possible charges being filed. Additionally four teenagers were charged in Pennsylvania, after a police investigation found detailed evidence of a plan to target Dunmore High School outside of Scranton, Pennsylvania, on April 20, 2024, the 25th anniversary of the attack. Text messages between the students planning the attack, claiming "dibs" on certain potential victims, and that they wanted "everything to go down like Columbine".

In August 2022, the perpetrator of the 2022 Bend, Oregon shooting wrote in an online manifesto he was partially influenced by the Columbine massacre.

New discoveries stress the possibility of spread, showing that there is a greater danger of more shootings nearby within about two weeks after an initial instance. Nevertheless, not all research concurs with this timing sequence.

One state's school shooting can influence the probability of shootings in schools of nearby states and the same state in upcoming years, stressing how these incidents are connected. For instance, divorce rate has a significant positive effect on the intensity level of school shooting cases. However, the percentage of minorities shows a negative impact, although not statistically significant yet. These results highlight the intricate social and economic elements involved, requiring broad-ranging approaches to tackle them well.

List of alleged copycat incidents

Date	Location	Attacker(s)	Casualties	Dead	Injured	Description
April 28, 1999	Taber, Alberta, Canada	Todd Cameron Smith	1 dead, 1 injured	1	1	The W. R. Myers High School shooting was the first documented Columbine copycat attack. The gunman, 14-year-old school dropout Todd Cameron Smith, reportedly "snapped" after watching news coverage about the Columbine High School massacre.
May 20, 1999	Conyers, Georgia, United States	Anthony "T.J." Solomon	0 dead, 6 injured	0	6	A month to the day after the Columbine High School massacre, 15-year-old student Anthony "T.J." Solomon opened fire with a .22-caliber rifle, wounding six students. A 15-year-old girl was hospitalized in critical condition, and the other victims suffered non-life-threatening injuries. Solomon attempted suicide with a revolver but was talked into surrendering by an assistant principal. Solomon left a note pledging allegiance to the Columbine attackers.
November 1, 1999	Bad Reichenhall, Germany	Martin Peyerl	5 dead (including perpetrator), 7 injured	5	7	Martin Peyerl was a German student who opened fire from his bedroom window, killing four people and wounded seven others before committing suicide. Before his attack, Peyerl reportedly told friends that the Columbine attack was "something we should do."
December 6, 1999	Fort Gibson, Oklahoma, United States	Seth Randall Trickey	0 dead, 5 injured	0	5	Trickey, a straight-A student with friends and no prior mental health issues or a history of violence, randomly fired 13 rounds from a handgun into a crowd of students outside of the school just prior to the school day starting. He was tackled by a teacher and police officer. Trickey had been reading about the Columbine shooting.
April 20, 2000	Ottawa, Ontario, Canada	15-year-old student	0 dead, 6 injured	0	6	On the one year anniversary of the Columbine attacks, a 15-year-old student at Cairine Wilson Secondary School inspired by the attacks stabbed another student he had previously had disagreements with - then began randomly stabbing others throughout the school. The principal at the time, Michael Jordan, talked the teenaged boy down and convinced him to give up the knife, but not before attempting to inflict wounds on his own wrists. The boy was afterwards described as a "loner" and had often been bullied and teased about his appearance.
March 5, 2001	Santee, California, United States	Charles Andrew Williams	2 dead, 13 injured	2	13	Charles Andrew "Andy" Williams perpetrated a mass shooting at Santana High School on March 5, 2001. In the shooting, two students were killed and 13 others were wounded.
March 22, 2001	El Cajon, California, United States	Jason Hoffman	0 dead, 6 injured (including perpetrator)	0	6	During the fifth period, minutes after lunch period had ended, 18-year-old Former GHHS Student, Jason Hoffman arrived on campus and opened fire with a shotgun on the attendance office, which also houses the principal and vice principals' offices, from the outside. Five people were either injured by shrapnel or suffered severe symptoms from the traumatic experience but few victims incurred bullet wounds. Hoffman was shot in the buttocks and jaw. He was arrested by police officer Rich Agundez, who had been on campus during school hours since the shooting two weeks earlier at a high school within the same district, Santana High School. Hoffman died from suicide by hanging in his San Diego Central Jail cell shortly before his sentencing on October 29, 2001.
April 26, 2002	Erfurt, Germany	Robert Steinhäuser	17 dead (including perpetrator), 1 injured	17	1	19-year-old Robert Steinhäuser, who was permanently expelled from school in October 2001, entered the Gutenberg-Gymnasium in Erfurt and shot and killed 13 staff members, two students and a police officer. He also wounded one other student. He then committed suicide.
September 28, 2004	Carmen de Patagones, Provincia de Buenos Aires, Argentina	Rafael Solich	3 dead, 5 injured	3	5	Rafael Solich watched the movie Elephant which was based on the Columbine massacre. He then became inspired and wanted to become like Eric and Dylan. He killed 3 and injured 5.
February 13, 2005	Ulster, New York, United States	Robert C. Bonelli, Jr.	0 dead, 2 injured	0	2	On February 13, 2005, Robert Bonelli, age 24, of Glasco, New York, entered the mall with a semi-automatic AK-47 Variant and began firing it in the mall's Best Buy shop. Panic ensued as employees and shoppers began to flee the mall. Bonelli moved into the mall's main corridor and continued firing his weapon until he ran out of ammunition. After emptying the assault rifle, he promptly dropped it. As Bonelli dropped the weapon, a mall employee grabbed his gun, and another tackled him. The mall was evacuated and Bonelli was taken into custody. No one was killed in the shooting, but two people, a 20-year-old National Guard recruiter and a 56-year-old male shopper, were wounded. After the incident, Ulster County investigators searched Bonelli's room at the home he shared with his father and found what Ulster County District Attorney Donald Williams described as "Columbine memorabilia". Officials described the young man as being fascinated by the Columbine High School massacre.
March 21, 2005	Red Lake, Minnesota, United States	Jeffrey James Weise	10 dead (including perpetrator), 5 injured	10	5	The Red Lake shootings were a spree killing that occurred on March 21, 2005, in two places on the Red Lake Indian Reservation in Red Lake, Minnesota, United States. That morning, 16-year-old Jeffrey Weise killed his grandfather (a tribal police officer) and his grandfather's girlfriend at their home. After taking his grandfather's police weapons and vest, Weise drove his grandfather's police vehicle to Red Lake Senior High School, where he had been a student some months before. Weise shot and killed seven people at the school and wounded five others. The dead included an unarmed security guard at the entrance of the school, then a teacher and five students. After the police arrived, Weise exchanged gunfire with them. After being wounded, he shot and killed himself, committing suicide in a vacant classroom.
November 26, 2005	Fayette, Maine, United States	Patrick Armstrong	1 dead, 0 injured	1	0	Armstrong murdered his neighbor, 14-year-old Marlee Johnston. Armstrong reportedly admired the Columbine killers.
March 14, 2006	Reno, Nevada, United States	James Scott Newman	0 dead, 2 injured	0	2	14-year-old student James Scott Newman shot and wounded two students in the hallway of Pine Middle School.
August 30, 2006	Hillsborough, North Carolina, United States	Alvaro Castillo	1 dead, 2 injured	1	2	18-year-old Alvaro Rafael Castillo opened fire at Orange High School with a rifle and shotgun, shooting eight times and wounding two students. Officers ordered him to stop firing and he immediately complied. Castillo killed his father with a firearm before driving to school in a van. In the van police officers found ammunition, pipe bombs, and other weapons.
September 13, 2006	Montreal, Quebec, Canada	Kimveer Gill	2 dead (including perpetrator), 19 injured	2	19	Kimveer Gill opened fire at Dawson College, near downtown Montreal. One victim, Anastasia De Sousa, died the next day at the hospital due to serious injuries, while another 19 were injured, eight of whom were listed in critical condition, with six requiring surgery. The gunman later committed suicide.
September 22, 2006	Pocatello, Idaho, United States	Brian Lee Draper, Torey Michael Adamcik	1 dead, 0 injured	1	0	Brian Draper and Torey Adamcik murdered a classmate at her home. At the trial, the prosecution revealed that Draper had said he was inspired by Harris and Klebold.
September 29, 2006	Cazenovia, Wisconsin, United States	Eric Hainstock	1 dead, 0 injured	1	0	Eric Hainstock brought a shotgun and a handgun to school and confronted the principal. The shotgun was wrestled away from him, but in a struggle over the handgun, Hainstock shot the principal, who died later of his wounds.
November 20, 2006	Emsdetten, Germany	Sebastian Bosse	1 dead (perpetrator), 37 injured	1	37	An 18-year-old former student entered the Geschwister Scholl school in western Germany with a sawed-off percussion rifle, a sawed-off 22-caliber bolt-action rifle, a caplock pistol and a set of explosive devices. The rampage started when Bosse shot and wounded five people with his guns. Police stormed the building, and the shooter released several smoke bombs as he retreated to the third floor, which caused injuries to people inside the school and police officers due to smoke inhalation. The suspect then took his own life.
April 10, 2007	Gresham, Oregon, United States	Chad Escobedo	0 dead, 10 injured	0	10	High school freshman Chad Escobedo shot the windows out of two classrooms from outside Springwater Trail High School, injuring ten students with shrapnel and broken glass, two of which required stitches. His motive was to shoot at a class in which he was enrolled, unhappy that the instructor had called his parents; the classrooms he hit, however, were not his intended target.
April 16, 2007	Blacksburg, Virginia, United States	Seung-Hui Cho	33 dead (including perpetrator), 17 injured	33	17	Cho killed 32 people (27 students and five faculty members) on the campus of Virginia Polytechnic Institute and State University in two separate incidents, about two hours apart. Another 17 people were injured at Norris, 6 of them when they jumped from second-story windows to escape. Cho committed suicide after police breached the main entrance doors.
November 7, 2007	Tuusula, Finland	Pekka-Eric Auvinen	9 dead (including perpetrator), 1 injured	9	1	18-year-old student Pekka-Eric Auvinen opened fire with a .22-caliber semi-automatic SIG Mosquito pistol at Jokela High School, in Tuusula, Finland. Six students, the school principal, and the school nurse were killed. The forty-minute attack ended when Auvinen shot himself in the head, later dying that evening at a Helsinki hospital.
August 27, 2007	Boulder, Colorado, United States	Kenton Astin	0 dead, 1 injured	0	1	Astin stabbed a student at the University of Colorado on the morning of August 27, 2007. Prior to the attack, he was shouting things like, "We are Columbine."
December 9, 2007	Arvada, Colorado, United States	Matthew Murray	5 dead (including perpetrator), 5 injured	5	5	Matthew J. Murray attacked the Youth with a Mission missionary training school in Arvada, Colorado, killing two and wounding two others. He drove to the New Life Church in Colorado Springs, Colorado where he killed two more people and wounded three before being shot by a security guard. Murray then committed suicide.
February 14, 2008	DeKalb, Illinois, United States	Steven Kazmierczak	6 dead (including perpetrator), 17 injured	6	17	The Northern Illinois University shooting was a school shooting that took place on February 14, 2008, at Northern Illinois University in DeKalb, Illinois. Steven Kazmierczak opened fire with a shotgun and three pistols in a crowd of students on campus, killing five students and injuring 17 more people, before fatally shooting himself.
September 23, 2008	Kauhajoki, Finland	Matti Saari	11 dead (including perpetrator), 1 injured	11	1	22-year-old culinary arts student Matti Saari opened fire at the Kauhajoki School of Hospitality of Seinäjoki University of Applied Sciences, in Kauhajoki, Finland, using a pistol. Nine students and a teacher died in the shooting, and he set their bodies and school property on fire. Saari then shot himself in the head, later dying at Tampere University Hospital.
March 11, 2009	Winnenden, Baden-Württemberg, Germany	Tim Kretschmer	16 dead (including perpetrator), 9 injured	16	9	17-year-old graduate student Tim Kretschmer opened fire with a semi-automatic 9mm Beretta pistol in two classrooms at the Albertville-Realschule, in Winnenden, Germany, killing nine students and one teacher; another two teachers were shot to death in a hallway by Kretschmer as he fled the school. Kretschmer then killed a bystander outside a nearby psychiatric hospital, and fled by vehicle to Wendlingen, a neighboring town, where he killed two bystanders at a car dealership and instigated a gun-battle with police. Kretschmer committed suicide during the exchange of gunfire.
May 18, 2009	Larose, Louisiana, United States	Justin Dorset	1 dead (perpetrator), 0 injured	1	0	Dorset attempted to kill his teacher, but his shot missed. He then committed suicide. Columbine-related materials were discovered at his home.
February 23, 2010	Littleton, Colorado, United States	Bruco Eastwood	0 dead, 2 injured	0	2	A 32-year-old gunman, identified as Bruco Strong Eagle Eastwood, armed with a .30–06 Winchester Model 70 bolt-action rifle, opened fire on students at Deer Creek Middle School at 3:30 pm (MST) as school was being let out in Littleton, Colorado. The gunman was later tackled by a math teacher and the teacher turned him into the police when they arrived on scene. The gunman shot and injured two students at the school before he was taken into custody. Eastwood was placed into a mental health facility for life.
December 28, 2010	Didcot, Oxfordshire, United Kingdom	Unknown	0 dead, 1 injured	0	1	A 16-year-old boy attempted to kill his sister. He had listed "shooting up schools like Columbine" as his occupation.
April 9, 2011	Alphen aan den Rijn, South Holland, Netherlands	Tristan van der Vlis	7 dead (including perpetrator), 17 injured	7	17	Tristan van der Vlis committed a mass shooting at a mall in the Netherlands. He researched the Columbine massacre.
March 20, 2012	Waller, Texas, United States	Trey Eric Sesler	3 dead, 0 injured	3	0	Sesler family murders: Trey Eric Sesler, 22, arrested for killing his parents and brother in Texas. He had planned on attacking his former school afterwards. Sesler was fascinated by the Columbine school massacre.
July 20, 2012	Aurora, Colorado, United States	James Eagan Holmes	12 dead, 58 injured	12	58	2012 Aurora, Colorado shooting, 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. Holmes did in-depth research about the Columbine massacre to see what the police response time would be and how much ammo he would need.
August 27, 2012	Baltimore, Maryland, United States	Robert Gladden, Jr.	0 dead, 1 injured	0	1	15-year-old Robert Gladden fired two shots with a shotgun inside the cafeteria at Perry Hall High School. A 17-year-old senior student was critically wounded in the lower back. Gladden was subdued by two faculty members and arrested by police.
October 14, 2013	Massama, Portugal	Gonçalo A., 15-year-old male student	0 dead, 4 injured	0	4	Gonçalo A. stabbed three students and a staff member at a school in Massama, Portugal. He told authorities that he wanted to mimic the Columbine and Sandy Hook school shootings.
October 21, 2013	Sparks, Nevada, United States	Jose Reyes	2 dead (including perpetrator), 2 injured	2	2	At approximately 7:15 am, a 12-year-old seventh grade student, Jose Reyes, opened fire with a Ruger 9 mm semi-automatic handgun at Sparks Middle School. A 12-year-old male student was hit in the shoulder and wounded. A teacher, Michael Landsberry, tried to intervene with Reyes and was fatally shot in the chest, while standing on a playground. Reyes then shot and wounded another male student in the abdomen who tried to come to Landsberry's assistance as he fell onto the ground. The shooter then committed suicide from a self-inflicted gunshot wound to the head.
December 13, 2013	Centennial, Colorado, United States	Karl Pierson	2 dead (including perpetrator), 0 injured	2	0	18-year-old male student Karl Pierson opened fire with a shotgun at Arapahoe High School, critically wounding a 17-year-old female student, Claire Davis. Pierson then committed suicide by shooting himself.
January 25, 2014	Columbia, Maryland, United States	Darion Marcus Aguilar	3 dead (including perpetrator), 5 injured	3	5	Aguilar was obsessed with mass shootings at school and malls. He shot and killed two mall employees before committing suicide. During the attack, he dressed as the Columbine killers.
April 9, 2014	Murrysville, Pennsylvania, United States	Alexander Brando Hribal	0 dead, 21 injured	0	21	Alex Hribal, a sophomore, came to school with two knives. He began roaming the halls and stabbing his classmates and a security guard. Before he was tackled by Sam King, the school's assistant principal, and taken into custody, he had injured 21 people.
April 29, 2014	Kennesaw, Georgia, United States	Geddy Kramer	1 dead (perpetrator), 6 injured	1	6	Geddy Kramer, 19, shot and wounded six co-workers at a FedEx facility and then committed suicide. He was reportedly obsessed with the Columbine shootings.
June 5, 2014	Seattle, Washington, United States	Aaron Rey Ybarra	1 dead, 2 injured	1	2	Aaron Ybarra killed one and wounded two others during a shooting at Seattle Pacific University. Ybarra was obsessed with the Columbine massacre, and may have visited the school.
June 8, 2014	Las Vegas, Nevada, United States	Jered and Amanda Miller	5 dead (including perpetrators), 0 injured	5	0	The 2014 Las Vegas shootings occurred on June 8, 2014, when a married couple, Jerad and Amanda Miller, committed a shooting in northeastern Las Vegas, Nevada. Five people died, including the two shooters. The couple, who espoused extreme anti-government views, first killed two Las Vegas police officers at a restaurant before fleeing into a Walmart, where they killed an intervening armed civilian named Joseph Wilcox. The couple died after engaging responding officers in a shootout in Walmart; police shot and killed Jerad, while Amanda committed suicide after being wounded. Friends of the Millers reported that they idolized Eric Harris and Dylan Klebold, the two perpetrators of the 1999 Columbine High School massacre, and wanted to follow in their footsteps.
July 22, 2015	Broken Arrow, Oklahoma, United States	Robert and Michael Bever	5 Dead, 1 injured	5	1	Robert and Michael Bever Murdered five members of their family and injured one. They expressed a desire to outdo the Columbine shooting.
August 26, 2015	Moneta, Virginia, United States	Vester Flanagan	3 dead (including perpetrator), 1 injured	3	1	Vester Lee Flanagan II killed Alison Parker and Adam Ward on live television. He later committed suicide. Flanagan expressed an admiration for the Columbine and Virginia Tech shooters.
October 1, 2015	Roseburg, Oregon, United States	Chris Harper-Mercer	10 dead (including perpetrator), 8 injured	10	8	Christopher Harper Mercer, 26, shot and killed nine people in a creative writing class at Umpqua Community College and shot and injured eight additional people. After a brief exchange of gunfire with police, during which he was injured, Mercer shot and killed himself.
September 28, 2016	Townville, South Carolina, United States	Jesse Osborne	2 dead, 3 injured	2	3	Osborne killed his father and then fired at an elementary school playground where he went to school as a child. He planned to kill more but his gun jammed.
March 16, 2017	Grasse, France	Killian Barbey	0 dead, 4 injured	0	4	The suspect in a French high school shooting allegedly watched videos of American high school attacks in preparation. He has been named a Killian Barbey, 16. Authorities have said that he was heavily armed with a rifle, two handguns and two grenades. The gunfire erupted at the Alexis de Tocqueville high school in Grasse at around 1 p.m. on March 16. The small city is located in the southeastern part of the country, less than 30 miles west of Nice in Alpes-Maritimes. The motive for the attack is "to be determined" by authorities.
June 8, 2017	Eaton Township, Pennsylvania, United States	Randy Stair	4 dead (including the perpetrator), 0 injured	4	0	24-year-old Randy Stair shot and killed three of his co-workers at Weis Markets before he committed suicide.
September 13, 2017	Rockford, Washington, United States	Caleb Joseph Sharpe	1 dead, 3 injured	1	3	Sharpe allegedly killed a fellow student who bullied him, then fired three random shots down hallway that wounded other students.
October 20, 2017	Goiânia, Estado de Goiás, Brazil	Unknown 14-year-old male student	2 dead, 4 injured	2	4	Goyases School shooting The student told police he was inspired by previous school shootings, including the Columbine and Realengo massacres.
December 7, 2017	Aztec, New Mexico, United States	William Atchison	3 dead (including perpetrator), 0 injured	3	0	Aztec High School shooting, On December 7, 2017, gunfire erupted at Aztec High School in Aztec, New Mexico, United States. The shooter, 21-year-old William Atchison, a former student at the school, 2017 killed two students, went inside the classroom where students had barricaded themselves in a small office area and shot several magazines, and then committed suicide.
January 17, 2018	Chelyabinsk, Russia	Unknown, ninth-grade male	0 dead, 1 injured	0	1	A ninth-grader stabbed another student at school. The attacker was allegedly a part of an online community that glorified Columbine.
February 14, 2018	Parkland, Florida, United States	Nikolas Cruz	17 dead, 17 injured	17	17	On February 14, 2018, a gunman opened fire at Marjory Stoneman Douglas High School in Parkland, Florida, killing seventeen students and staff members and injuring seventeen others. Days before the shooting, the gunman viewed several videos glorifying Columbine.
April 18, 2018	Sterlitmak, Russia	Artyom Tagirov	0 dead, 4 injured (including perpetrator)	0	4	Tagirov injured three in a stabbing attack in Sterlitmak, Russia before attempting suicide. He praised the Columbine attack on social media.
April 20, 2018	Ocala, Florida, United States	Sky Bouche	0 dead, 1 injured	0	1	Sky Bouche, 19, blended in with students and entered the school with a shotgun concealed in a guitar case. He then fired at a classroom door, injuring a 17-year-old boy in the ankle. The school resource officer arrived on the scene within minutes; Bouche was taken into custody without incident.
May 18, 2018	Santa Fe, Texas, United States	Dimitrios Pagourtzis	10 dead, 14 injured (including perpetrator)	10	14	On May 18, 2018, a school shooting occurred at Santa Fe High School in Santa Fe, Texas, United States, in the Houston metropolitan area. Ten people – eight students and two teachers – were fatally shot, and thirteen others were wounded. Dimitrios Pagourtzis, a 17-year-old student at the school, was taken into custody.
May 25, 2018	Noblesville, Indiana, United States	David Moore	0 dead, 2 injured	0	2	The 2018 Noblesville West Middle School shooting occurred on May 25, 2018, in Noblesville, Indiana when a 13-year-old student shot and injured teacher Jason Seaman and student Ella Whistler.
July 22, 2018	Toronto, Ontario, Canada	Faisal Hussain	3 dead (including perpetrator), 13 injured	3	13	Hussain killed two and wounded 13 in a mass shooting on Danforth Avenue in Toronto. In high school, Hussain openly praised the Columbine school shooting. He became obsessed with the 'incel culture,' particularly Elliot Rodger and Alek Minassian.
October 17, 2018	Kerch, Crimea, Russia	Vladislav Roslyakov	21 dead (including perpetrator), 70 injured	21	70	The Kerch Polytechnic College massacre was a school shooting and bomb attack that occurred in Kerch, Crimea, on October 17, 2018.
March 13, 2019	Suzano, São Paulo, Brazil	Guilherme Taucci Monteiro, Luiz Henrique de Castro	10 dead (including perpetrators), 11 injured	10	11	The Suzano school shooting took place on March 13, 2019, at the Professor Raul Brasil State School in the Brazilian municipality of Suzano, São Paulo State. The perpetrators, Guilherme Taucci Monteiro and Luiz Henrique de Castro, both former students at the school, killed five students and two school employees while wearing clothes resembling those worn by the lead characters of Elephant, a film based on the Columbine shooting. Before the attack, in a car shop near the school, the pair also killed Monteiro's uncle.
May 7, 2019	Douglas County, Colorado, United States	Alec McKinney & Devon Erickson	1 dead, 6 injured	1	6	2019 STEM School Highlands Ranch shooting, Alec McKinney and Devon Erickson went to their school and shot and killed 1 student and injured 6 others; 2 others were injured by friendly fire. Erickson and McKinney began researching the Columbine shooting after Sol Pais, a teenage girl obsessed with Columbine, flew to Colorado and committed suicide.
May 27, 2019	Brześć Kujawski, Kujawsko-Pomorskie, Poland	Marek Nowak	0 dead, 2 injured	0	2	An 18-year-old former student known only as Marek Nowak detonated explosives and shot and wounded an 11-year-old girl and a 59-year-old female janitor, at Władysław Łokietek Elementary School. The perpetrator had multiple Columbine-related pictures and internet memes on his Facebook account.
May 28, 2019	Volsk, Saratov Region, Russia	Daniil Pulkin	0 dead, 1 injured	0	1	Pulkin committed an axe attack in Volsk, Russia. He was inspired primarily by Vladislav Roslyakov, but also expressed interest in the Columbine and STEM Highland Ranch school shootings.
Prior to June 2, 2019	Merrimack County, New Hampshire, United States	Griffin Furlotte	0 dead, 3 injured	0	3	Furlotte allegedly raped three female students. He had previously threatened to commit a school shooting at Pembroke Academy in Pembroke, New Hampshire; the threats included a reference to the Columbine High School massacre.
January 10, 2020	Torreon, Coahuila, Mexico	José Ángel Ramos Betts	2 dead (including perpetrator), 6 injured	2	6	11-year-old José Ángel Ramos Betts opened fire inside a private school in Torreon, Mexico. He killed 1 teacher and wounded 6 others before committing suicide.
January 25, 2020	Chełm, Poland	Łukasz Wach	1 dead, 1 injured	1	1	14-year-old Łukasz Wach attacked his family with a knife at home, killing his stepmother and wounding her son, after which he went to a local culture house, where he possibly planned the attack. He was obsessed with murderers and crimes, and he nicknamed himself "Reb", the online nickname of Harris, in one of his social media accounts.
October 12, 2020	Nizhny Novgorod Oblast, Russia	Daniil Monakhov	5 dead (including perpetrator), 2 injured	5	2	Daniil Monakhov killed 4 people and wounded 2 more before shooting himself. He was obsessed with Columbine and he was known for threatening to do a school shooting, he wrote several references to Columbine on social networks.
August 28, 2022	Bend, Oregon, United States	Ethan Blair Miller	3 dead (including perpetrator), 2 injured	3	2	2022 Bend, Oregon shooting, 20 year-old Ethan Miller opened fire at a safeway Grocery store armed with AR-15 type rifle and a shotgun, killing 2 and injuring 2 others before committing suicide.
September 26, 2022	Izhevsk, Udmurtia, Russia	Artem Kazantsev	19 dead (including perpetrator), 23 injured	19	23	34-year-old Artem Kazantsev, who was armed with two pistols, attacked the School No. 88, killing 18 and injuring 23 others. He was wearing a neo-Nazi shirt while committing the attack, and also honoring Harris and Klebold by having braided key chains on his weapons.
November 25, 2022	Aracruz, Espírito Santo, Brazil	Gabriel Rodrigues Castiglioni	4 dead, 12 injured	4	12	Aracruz school shootings, 17-year-old Gabriel Rodrigues dressed in a military camouflage uniform, armband with swastika, skull mask and bucket hat, broke into a public school, Primo Bitti Ensino Fundamental e Médio, and a private school in city of Aracruz, Espírito Santo. The attacks on the two schools resulted in four deaths and 12 injuries.
January 4, 2024	Perry, Iowa, United States	Dylan Butler	3 dead (including the perpetrator), 6 injured	3	6	17-year old student at Perry High School killed a 6th grade student and injured 7 others (one of whom, the principal of the school, died 10 days after the attack) during a morning breakfast on the first day after winter break. Police found him armed with a pump-action shotgun and a small-caliber handgun. The middle school attached to the high school was cleared by 8:25 a.m., and the high school was evacuated by 8:27 a.m. The shooter also planted an improvised explosive device inside the school.

In popular culture

A video game called Super Columbine Massacre RPG! was based on the massacre.

The 2016 biographical film I'm Not Ashamed, based on the journals of Rachel Scott, includes alleged glimpses of Harris's and Klebold's lives and interactions with other students at Columbine High School. The 1999 black comedy, Duck! The Carbine High Massacre is inspired by the Columbine massacre. The 2003 Gus Van Sant film Elephant (which won the Palme d'Or at that year's Cannes Film Festival) depicts a fictional school shooting, but is based in part on the Columbine massacre. The 2003 Ben Coccio film Zero Day was also based on the massacre.

The 2005 Lifetime film Dawn Anna is based on the struggles of Dawn Anna Townsend, whose daughter Lauren was killed in the massacre.

The first documentary on the massacre may have been the TLC documentary Lost Boys in 2000. The 2002 Michael Moore documentary film Bowling for Columbine, which explores the massacre in the context of American gun culture, won several awards including the Academy Award for Best Documentary Feature. Also in 2002, A&E made "Columbine: Understanding Why".

Rapper Eminem references the shooting multiple times throughout his discography. Most famously, "I'm Back" off of The Marshall Mathers LP (2000) contained a line about Columbine that was censored. He references this censorship in "Rap God" (The Marshall Mathers LP 2, 2013) and repeats the line, saying it will not be censored this time because he was not as famous as when "I'm Back" was released. In 2024, he referenced the event once again in his song "Lucifer"

Rapper Tyler, the Creator references the shooting in his song "Yonkers" from his album Goblin. also his song "Pigs" from his album Wolf was inspired by the two shooters.

Fred Durst references the Columbine shooting in the Limp Bizkit song "Head for the Barricade", which is on the 2003 album Results May Vary, and the reference was not censored on the explicit or edited versions of the album.

In 2004, the shooting was dramatized in the documentary Zero Hour, narrated by David Morrissey. In 2007, the massacre was documented in an episode of the National Geographic Channel documentary series The Final Report.

The 2009 film April Showers, which was written and directed by Andrew Robinson, who was a senior at Columbine High School during the shooting, was based on Columbine. The 2013 film Kids for Cash about the kids for cash scandal detail it as part of the "zero-tolerance" policy in the wake of the Columbine shootings.

Columbine students, Jonathan and Stephen Cohen wrote a song called "Friend of Mine (Columbine)", which briefly received airplay in the US after being performed at a memorial service broadcast on USA-wide television. The song was pressed to CD, with the proceeds benefiting families affected by the massacre, and over 10,000 copies were ordered. Shortly following the release of the CD single, the song was also featured on the Lullaby for Columbine CD.

Since the advent of online social media, a fandom for shooters Harris and Klebold has had a documented presence on social media sites, especially Tumblr. Fans of Harris and Klebold refer to themselves as "Columbiners." An article published in 2015 in the Journal of Transformative Works, a scholarly journal which focuses on the sociology of fandoms, noted that Columbiners were not fundamentally functionally different from more mainstream fandoms. Columbiners create fan art and fan fiction, and have a scholarly interest in the shooting.