How often do mass killings happen at work? Data shows public shootings are fraction of US violence.

Mass killings that unfold in public places are a small fraction of all U.S. mass killings.Workplace killings by employees are rare, criminologist James Alan Fox says.Since 2006, about 3% of total mass killings occurred at a workplace and were perpetrated by a current or former employee.Six people died and several others were injured after authorities say a store manager opened fire at a Chesapeake, Virginia, Walmart Tuesday night, another in a string of fatal shootings across the nation.Officers found the shooter dead of an apparent self-inflicted gunshot wound.The tragedy, which took place in the store break room, comes days after at least five people were killed and at least 17 others injured at the Club Q shooting in Colorado Springs, Colorado.So far this year, 202 people have died in 40 mass killings across the nation, according to a database of mass killings maintained through a partnership between USA TODAY, The Associated Press, and Northeastern University.Mass killings that unfold in public places are a small fraction of all U.S. mass killings. Those that occur at a workplace are an even smaller portion.And workplace killings perpetrated by employees are comparatively rare, say experts like James Alan Fox, a criminologist and professor at Northeastern University. Here’s what to know.THE LATEST:Walmart manager opens fire in break room, killing 6, in Chesapeake, VirginiaHow often do workplace mass killings occur?There have been 17 mass killings at a workplace by a current or former employee since 2006, resulting in 106 deaths, according to the database. That’s about 3% of total mass killing incidents since 2006.“In terms of workplace homicides, most are actually committed not by employees,” Fox said.When an employee is the perpetrator of a workplace shooting, the assailant typically has felt wronged by the company, according to Fox.“You can’t kill the company, but still can hurt the company by killing its employees,” he said. “It’s typically anger and hostility towards the job or the company.”In 2020, a brewery employee at Milwaukee, Wisconsin’s Molson Coors campus shot and killed five coworkers before killing himself. It was the 13th mass workplace shooting by a current or former employee since 2006, according to the database.The year before, in February 2019, an employee at a manufacturing plant in Aurora, Illinois, killed five co-workers. Officers killed the gunman following a 90-minute shootout.Many workplace firearm-related homicides that aren’t classified as mass shootings are tied to robberies, and some to disgruntled customers or clients, Fox explained. Over the past decade, the number of firearm-related workplace homicides has fluctuated between 350 and 400, according to data from the Bureau of Labor Statistics Census of Fatal Occupational Injuries. In 2018, 351 people were killed in a workplace firearm-related homicide.What defines a mass killing?A mass killing is typically defined as an incident in which four or more people are killed, not including the perpetrator.Mass killings that unfold in public places like schools, markets or places of worship make up a small fraction of all U.S. mass killings. Of this year’s 40 mass killings, seven, including the Chesapeake tragedy, were shootings that occurred in public places. Most occur in private homes. Over the past 16 years, about 70% of mass killings occurred in a residence or other shelter.Since 2006, 2,742 people have died in 526 mass killings that occurred in all types of places, and the majority were shootings, according to the USA TODAY, AP and Northeastern database. Of those, 361 victims died in 52 mass killings that unfolded in public places such as commercial, retail, and entertainment settings.One 2016 analysis published in a criminology journal found during a four-year period, a failed or estranged relationship was the most common reason behind a mass killing.Overall, roughly 45,000 people a year die of firearm-related injuries, according to 2020 data from the Centers for Disease Control and Prevention.More:Gun violence is a public health epidemic, experts say. It needs to be treated like one.More:Suspect faces 5 counts of murder, hate crimes in Colorado Springs nightclub massacre: UpdatesContributing: John Bacon, Thao Nguyen and Mitchell Thorson, USA TODAY; The Associated Press.