However, other types of gun violence rose from 2019 to 2020, according to the Gun Violence Project

Prior to last Tuesday, America had gone a year without a public mass shooting, defined as involving four or more fatal victims, according to the Violence Project, a non-profit research organization dedicated to reducing gun violence.

The last mass shooting in the U.S. took place in March 2020, when a man killed four people at a gas station in Springfield, Missouri. That shooting occurred just prior to the imposition of widespread restrictions on schools, workplaces, and businesses due to the COVID-19 pandemic.

There have now been two such tragedies in the last week, following the murders Monday of 10 people, including a police officer, at a Boulder, Colorado, grocery store, and the killings of eight people in the Atlanta area last week.

Supermarket Shooting, Boulder
The scene outside Monday's mass shooting
| Credit: David Zalubowski/AP/Shutterstock

The two previous years saw the most mass shootings in public places on record, with 10 mass shootings in 2018 and nine in 2019, according to Jillian Peterson, an associate professor of criminal justice at Hamline University in St. Paul, Minn., and a co-founder of the Violence Project, who spoke to the New York Times.

Supermarket Shooting, Boulder
Scene in Boulder, Colorado, after shooting
| Credit: JASON CONNOLLY/AFP via Getty Images

Peterson told the Times that, since some shooters mimic the actions of other killers, the media's constant coverage of the coronavirus and a lack of high-profile mass shootings may also have contributed to fewer public mass shootings.

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Prior to the recent mass shootings, during the year-long lull, "There had been a hope that maybe we broke the cycle and maybe we won't return," said Peterson. "Now that it's back, a number of scholars are really concerned."

However, data from the Gun Violence Archive shows other types of gun violence increased significantly in 2020.

Data from the Gun Violence Archive shows deaths from homicides and defensive gun use rose from 15,440 in 2019 to 19,380 in 2020.

In all, there were more than 600 shootings in which four or more people were shot by one person compared with 417 in 2019, according to the Gun Violence Archive.

Peterson said many of those shootings involved gang violence, fights and domestic incidents, where the perpetrator knew the victims.

She noted early research indicates financial stress along with rising unemployment and drug and alcohol use during the pandemic contributed to an overall increase in shootings in 2020.