The École Polytechnique massacre, also known as the Montreal massacre, was an antifeminist mass shooting that occurred on December 6, 1989, at the École Polytechnique de Montréal in Montreal, Quebec, Canada. Fourteen women were murdered; another ten women and four men were injured. The perpetrator was 25-year-old Marc Lépine, armed with a legally obtained Ruger Mini-14, 30-round high-capacity magazines, and a hunting knife. He began his rampage at a mechanical engineering class at the École Polytechnique, where he separated the male and female students, ordering the men to leave. He shot all nine women in the room, killing six. For nearly 20 minutes the shooter moved through corridors on multiple floors of the building, the cafeteria, and another classroom, targeting women. He wounded more students and killed eight more women before fatally shooting himself.
A school shooting and attempted bombing 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 were killed in the school library, where Harris and Klebold subsequently died by suicide. Twenty-one additional people were injured by gunshots, and gunfire was 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 December 2012. It is still considered one of the most infamous massacres in the U.S. for inspiring many other school shootings and bombings; the word "Columbine" has since become a byword for modern school shootings. As of 2025, Columbine is still the deadliest school shooting in Colorado, the deadliest high school shooting in the United States to happen west of the Mississippi River, and one of the deadliest mass shootings in the United States.
Edmond is a city in Oklahoma County, Oklahoma, United States. It is a part of the Oklahoma City metropolitan area, located in Central Oklahoma. The population was 94,428 according to the 2020 United States Census, a 16% increase from 2010. making it the 5th most populous city in Oklahoma.
Going postal is an American English slang phrase referring to becoming extremely and uncontrollably angry, often to the point of violence, and usually in a workplace environment. The expression derives from a series of incidents from 1986 onward in which United States Postal Service (USPS) workers shot and killed managers, fellow workers, police officers and members of the general public in acts of mass murder. Between 1970 and 1997, more than 40 people were killed by then-current or former employees in at least 20 incidents of workplace rage. Between 1986 and 2011, workplace shootings happened roughly twice per year, with an average of 1.18 people killed per year.
Columbine High School (CHS) is a public high school in Columbine, Colorado, United States, in the Denver metropolitan area. It is part of the Jefferson County Public Schools district.
The San Ysidro McDonald's massacre was a 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.
Edmond Memorial High School is a public secondary school located in Edmond, Oklahoma, one of three high schools in the Edmond school district. It serves approximately 2,300 students.
Workplace violence, violence in the workplace, or occupational violence refers to violence, usually in the form of physical abuse or threat, that creates a risk to the health and safety of an employee or multiple employees. The National Institute for Occupational Safety and Health defines worker on worker, personal relationship, customer/client, and criminal intent all as categories of violence in the workplace. These four categories are further broken down into three levels: Level one displays early warning signs of violence, Level two is slightly more violent, and level three is significantly violent. Many workplaces have initiated programs and protocols to protect their workers as the Occupational Health Act of 1970 states that employers must provide an environment in which employees are free of harm or harmful conditions.
Edmond Santa Fe High School is a public high school located in Edmond, Oklahoma, United States. Founded in 1993, Santa Fe is one of three traditional high schools in the Edmond Public Schools district, along with Edmond Memorial High School and Edmond North High School. The school's mascot is the Wolf and the school colors are forest green and gray.
Roger Dale Stafford was a convicted serial killer executed for the 1978 murders of the Lorenz Family and six employees of a Sirloin Stockade restaurant in Oklahoma. Stafford never acknowledged his guilt, but Stafford's wife, Verna, implicated him in a total of 34 murders in seven different states.
The Westside Middle School shooting was a mass shooting that occurred on March 24, 1998, at Westside Middle School in unincorporated Craighead County, Arkansas near the city of Jonesboro. 13-year-old Mitchell Johnson and 11-year-old Andrew Golden opened fire on the school, shooting and killing five people with multiple weapons, and both were arrested when they attempted to flee the scene. Ten others were wounded. Golden and Johnson were convicted of five murders and ten assaults, and were imprisoned until each turned 21 years of age. After the 1992 Lindhurst High School shooting that killed four people in Olivehurst, California, the massacre was the deadliest non-college school shooting in contemporary U.S. history until the April 1999 Columbine High School massacre. As of 2025, the incident is the deadliest mass shooting at a middle school in U.S. history.
The Springhill massacre was an incident in which five Catholic residents were killed by the British Army in the Springhill estate in West Belfast, Northern Ireland, on 9 July 1972, during the Troubles. Three of the victims were teenagers, including a 13-year-old girl, and another was a Catholic priest waving a white flag as he went to attend one of the injured.
Murder By Proxy: How America Went Postal is a 2010 American documentary film that examines the phenomenon of spree killing, particularly in a workplace, that became known in the United States as "going postal".
On December 14, 2012, a mass shooting occurred at the Sandy Hook Elementary School in Newtown, Connecticut, United States. The perpetrator, 20-year-old Adam Lanza, shot and killed 26 people. The victims were 20 children between six and seven years old, and 6 adult staff members. Earlier that day, before driving to the school, Lanza fatally shot his mother at their Newtown home. As first responders arrived at the school, Lanza killed himself with a gunshot to the head.
The Broken Arrow murders, otherwise known as the Bever family massacre, were a familicide and mass stabbing that occurred on July 22, 2015, in Broken Arrow, Oklahoma. The perpetrators, Robert and Michael Bever, murdered their parents and 3 siblings. It was the deadliest crime and mass murder in the city of Broken Arrow, until a murder-suicide in October 2022 which killed 8 people.
In the early hours on the morning of June 8, 2017, employees at a Weis Markets supermarket in Eaton Township, Pennsylvania, United States, were stocking and closing the store for the night. Shortly before 1:00 a.m., 24-year-old Randy Stair barricaded the exits of the store and proceeded to shoot and kill three of his co-workers before fatally shooting himself.
On November 14, 1991, a mass shooting occurred at the United States Post Office in Royal Oak, Michigan, United States. In the incident, a disgruntled former postal worker, identified as 31-year-old Thomas McIlvane, shot and killed four post office employees before committing suicide.
