Mass murder is the violent crime of killing a number of people, typically simultaneously or over a relatively short period of time and in close geographic proximity.[1][2] A mass murder typically occurs in a single location where one or more persons kill several others.[3][4]
In the United States, Congress defined mass murders as the killing of three or more persons during an event with no "cooling-off period" between the homicides.[5] The Investigative Assistance for Violent Crimes Act of 2012, passed in the aftermath of the Sandy Hook Elementary School shooting, clarified the statutory authority for federal law enforcement agencies, including those in the Departments of Justice and Homeland Security, to assist state law enforcement agencies, and mandated across federal agencies a definition of "mass killing" as three or more killings during an incident.[6][7][8][9]
A mass murder may be further classified as a mass shooting or a mass stabbing. Mass murderers differ from spree killers, who kill at two or more locations with almost no time break between murders and are not defined by the number of victims, and serial killers, who kill people over long periods of time.[10]
By terrorist organizations
Many terrorist groups in recent times have used the tactic of killing many victims to fulfill their political aims. Such incidents have included:
Mass murderers may be categorized into killers of family, of coworkers, of students, and of random strangers. Their motives vary.[11] One motivation for mass murder is revenge, but other motivations are possible, including the need for attention or fame.[12][13][14]
Analysis of the Columbine High School massacre and other incidents where law enforcement officers waited for backup has resulted in changed recommendations regarding what victims, bystanders, and law enforcement officers should do. In the Columbine shooting, the perpetrators, Eric Harris and Dylan Klebold, were able to murder 13 people, then commit suicide before the first SWAT team even entered the school. Average response time by law enforcement to a mass shooting is typically much longer than the time the shooter is engaged in killing. While immediate action may be extremely dangerous, it could save lives which would be lost if victims and bystanders involved in the situation remain passive, or law enforcement response is delayed until overwhelming force can be deployed. It is recommended that victims and bystanders involved in the incident take active steps to flee, hide, or fight the shooter and that law enforcement officers present or first arriving at the scene attempt immediately to engage the shooter. In many instances, immediate action by victims, bystanders, or law enforcement officers has saved lives.[16] However, law enforcement programs and actions have so far been unable to reduce the total number of incidents. In 2020, a record number of 600 mass shootings occurred.[17]
Criticism as an analytical category
Commentators have pointed out that there are a wide variety of ways that homicides with more than several victims might be classified. Such incidents can be, and have been even in recent decades, classified many different ways including "as a mass shooting; as a school shooting; as mass murder; as workplace violence...; as a crime involving an assault rifle; as a case of a mentally ill person committing acts of violence; and so on."[18]
How such rarely occurring incidents of homicide are classified tends to change significantly with time. "In the 1960s and 1970s,... it was understood that the key feature of [a number of such] cases was a high body count. These early discussions of mass murder lumped together [a variety of] cases that varied along what would come to be seen as important dimensions:
Time: Did the killings occur more or less simultaneously, or did they extend over several days, months, or years?
Place: Did the killings occur in a single location, or in a variety of places?
In the late decades of the 20th century and early years of the 2000s, the most popular classifications moved to include method, time and place.
While such classifications may assist in gaining human meaning, as human-selected categories, they can also carry significant meaning and reflect a particular point of view of the commentator who assigned the descriptor.[18]
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Best, Joel (June 16, 2013). "How Should We Classify the Sandy Hook Killings?: The social construction of a mass shooting epidemic". Reason. Retrieved June 18, 2013. it is possible to characterize Newtown as an instance of a lot of different social problems: as a mass shooting; as a school shooting; as mass murder; as workplace violence (remember the staff members who were killed were at work); as a crime involving an assault rifle; as a case of a mentally ill person committing acts of violence; and so on. We expect journalists to have a sort of sociological imagination, to help us understand incidents as instances. And we can understand why advocates for gun control, mental health, or other causes might favor particular labels but we need to appreciate there is no One True Classification, that the categories we use are merely tools that may help us better understand what [is] happening in our society.