The Columbine High School massacre, commonly referred to as Columbine, was a school shooting and attempted bombing that occurred on April 20, 1999, at Columbine High School in Columbine, Colorado, United States. The perpetrators, twelfth-grade students Eric Harris and Dylan Klebold, murdered twelve students and one teacher. Ten of the twelve students killed were in the school library, where Harris and Klebold subsequently committed suicide. Twenty-one additional people were injured by gunshots, and gunfire was also exchanged with the police. Another three people were injured trying to escape. The Columbine massacre was the deadliest mass shooting at a K-12 school in U.S. history, until it was surpassed by the Sandy Hook Elementary School shooting in December 2012, and later the Uvalde school shooting in May 2022, and the deadliest mass shooting at a high school in U.S. history until the Parkland high school shooting in February 2018. Columbine still remains both the deadliest mass shooting and the deadliest school shooting to occur in the U.S. state of Colorado.
The San Ysidro McDonald's massacre was an act of mass murder which occurred at a McDonald's restaurant in the San Ysidro neighborhood of San Diego, California, on July 18, 1984. The perpetrator, 41-year-old James Huberty, fatally shot 21 people and wounded 19 others before being killed by a police sniper approximately 77 minutes after he had first opened fire.
The Trolley Square shooting was a mass shooting that occurred on the evening of February 12, 2007, at Trolley Square Mall in Salt Lake City, Utah, United States. A gunman identified as Sulejman Talović killed five bystanders and wounded four others before being shot dead by several members of the Salt Lake City Police Department. Authorities were not able to determine a motive.
The Crandon shooting was a mass murder that occurred about 2:45 a.m. CDT on October 7, 2007, at a post-homecoming party inside a duplex in Crandon, Wisconsin, United States. The perpetrator, 20-year-old Tyler James Peterson, who was a full-time deputy in the Forest County Sheriff's Department and a part-time officer with the Crandon Police Department, shot and killed six people and critically injured a seventh before committing suicide. One of the victims, 18-year-old Jordanne Michele Murray, was Peterson's former girlfriend, and it was believed that a dispute within the apartment motivated the shooting.
The Kauhajoki school shooting occurred on 23 September 2008 at the Seinäjoki University of Applied Sciences (SeAMK) in Kauhajoki, Finland. The gunman, 22-year-old student Matti Juhani Saari, shot and killed ten people with a Walther P22 Target semi-automatic pistol, before shooting himself in the head. He died a few hours later at Tampere University Hospital. One woman was injured but was in a stable condition.
On March 10, 2009, Michael Kenneth McLendon, 28, fatally shot ten people and wounded six others between the communities of Kinston, Samson, and Geneva, Alabama. McLendon's shooting spree was the deadliest mass shooting in Alabama's history.
On September 6, 2011, a mass shooting occurred in a branch of the IHOP in Carson City, Nevada, United States. A gunman, identified as 32-year-old Eduardo Sencion, killed four people, including three members of the National Guard, and wounded seven others before fatally shooting himself.
On October 12, 2011, a mass shooting occurred at the Salon Meritage hair salon in Seal Beach, California. Eight people inside the salon and one person in the parking lot were shot, and only one victim survived. It remains the deadliest mass killing in Orange County history.
The Chlorane Bar attack was a mass shooting at a city centre pub on 5 June 1976 in Belfast, Northern Ireland. It was carried out by the Ulster Volunteer Force (UVF), an Ulster loyalist paramilitary organisation, apparently in retaliation for the Provisional IRA bombing attack on the Times Bar on York Road, in which two Protestant civilians were killed. In the Chlorane attack, five civilian men were killed; three Catholics and two Protestants. The gunmen were militants from the UVF Belfast Brigade's Shankill Road battalion. The assault was a joint operation by the platoons based at the Brown Bear and the Windsor Bar, drinking haunts in the Shankill Road district frequented by UVF members.
On December 11, 2012, a shooting occurred at the Clackamas Town Center in the relatively urban section of Clackamas County, just outside the city of Portland, Oregon, United States. The gunman, 22-year-old Jacob Tyler Roberts, ran into the shopping center wearing black clothing and a white expressionless facial mask and sporadically opened fire using a Stag Arms AR-15 rifle stolen from a friend. He fired a total of 17 shots, killing two people and seriously wounding a third. Many shots were ricochets. Having attempted to reload his weapon and dropping three magazines, Roberts entered an employee-only back stairwell that runs behind all stores in the mall and committed suicide after descending one level. He had no connection to any of his victims, and it was believed to be a random act of violence.
On June 7, 2013, a spree shooting occurred in Santa Monica, California. Its catalyst was a domestic dispute and subsequent fire at a home, followed by a series of shootings near and on the Santa Monica College campus. Six people were killed, including the suspect, and four injured. The shooter — 23-year-old John Zawahri — was killed by police officers when he exchanged gunfire with them at the Santa Monica College library.
The 2014 Montgomery County shootings were a killing spree that occurred in Montgomery County, Pennsylvania, United States, on December 15, 2014. The killings began at about 3:30 a.m. A woman was found dead in Lower Salford Township, two others were found dead in Lansdale, and three more were found in Souderton along with a wounded teenage boy. Police identified the suspected killer as 35-year-old Bradley William Stone of Pennsburg, Pennsylvania, and the victims were his ex-wife and her family members. Most of the victims were shot, although some were also stabbed with a knife. After an extensive manhunt, Stone was found dead on the day after the killings in the woods near his home. He reportedly committed suicide by overdosing on several drugs.
On August 8, 2015, a mass shooting occurred inside a home in northern Harris County, Texas, near Houston. David Ray Conley III, 48, broke into his former home and held hostage Valerie and Dwayne Jackson, Sr., along with six children, including his own 13-year-old son. Over the course of nine hours, he shot and killed the entire family. He then engaged in a shootout with responding police before surrendering.
The University of Texas tower shooting was an act of mass murder which occurred on August 1, 1966, at the University of Texas at Austin. The perpetrator, 25-year-old Marine veteran Charles Whitman, indiscriminately fired at members of the public both within the Main Building tower and from the tower's observation deck. He shot and killed 15 people, including an unborn child, and injured 31 others before he was killed by two Austin Police Department officers approximately 96 minutes after first opening fire from the observation deck.
On October 1, 2017, a mass shooting occurred when 64-year-old Stephen Paddock opened fire on the crowd attending the Route 91 Harvest music festival on the Las Vegas Strip in Nevada from his 32nd-floor suites in the Mandalay Bay hotel. He fired more than 1,000 rounds, killing 60 people and wounding at least 413. The ensuing panic brought the total number of injured to approximately 867. About an hour later, he was found dead in his room from a self-inflicted gunshot wound. The motive for the shooting is officially undetermined.
On February 15, 2019, a mass shooting took place at Henry Pratt Company in Aurora, Illinois, United States. Six people died, including the perpetrator, 45-year-old former employee Gary Montez Martin, who was shot and killed by responding police officers. Six others were injured, including five police officers.
On July 28, 2019, a mass shooting occurred at the Gilroy Garlic Festival in Gilroy, California. The gunman killed three people and wounded 17 others before killing himself after a shootout with responding police officers.
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, 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.
On March 22, 2021, a mass shooting occurred at a King Soopers supermarket in Boulder, Colorado, United States. Ten people were killed, including a local on-duty police officer. The alleged shooter, 21-year-old Ahmad Al Aliwi Al-Issa, was arrested after being shot in the right leg. He was temporarily hospitalized before being moved to the county jail. After undergoing mental evaluations during the legal proceedings, Al-Issa was found mentally incompetent to stand trial in December 2021 and in April 2022. On August 23, 2023, prosecutors announced that Al-Issa was mentally competent to stand trial; a judge ruled as such on October 6 of that same year.
On October 13, 2022, a mass shooting occurred in the Hedingham neighborhood of Raleigh, North Carolina, United States. Five people were killed, and two others were injured. The accused, a male juvenile named Austin Thompson, was detained after being cornered by police at a nearby residence and was in critical condition from a gunshot wound to the head sustained during the incident. Thompson survived his head injury and has begun to receive physical rehabilitation. He was transferred from a hospital to the medical unit of a juvenile correctional facility.
