Criminologists say the shared burdens of 2020's public health crisis invoked a spirit of community that deterred would-be mass murderers, but data shows there were more shooting deaths overall last year than in 2019.

Data compiled by the Associated Press, USA Today, and Northeastern University found there were two public mass killings– defined by the agency as one that claimed four or more lives, not counting the shooter – last year.

The first was on Feb. 26, when a worker at a Milwaukee brewery killed five co-workers before turning the gun on himself. The other was on March 15, when a man killed four people in Springfield, Missouri, including a police officer, before taking his own life.

The public mass shooting numbers were considerably lower compared to 2019 and 2018 which saw nine and 10 shootings, respectively.

James Alan Fox, a criminologist at Northeastern University in Boston, told the AP that some of the social pressures that could trigger someone to commit mass murder were absent due to the pandemic.

“The thing about mass shooters is they tend to be people who feel that they are the victims of injustice. Well, lots of people now are suffering, not just them,” he explained.

“It’s hard to say right now that your own plight is unique or unfair. It may not feel good, but there’s certainly reason for it. And it’s not because of something someone’s doing to you. It’s really the pandemic, which is a thing, not a person.”

The non-profit group Gun Violence Archive found there were 39,526 gun-related deaths in 2019. Of those, more than half were suicides. Mass shootings, characterized as a spree that leaves at least four people shot, totaled 417, while mass murders totaled 31.

For 2020, there were 43,500 gun-related deaths, of which some 24,000 were suicides. There were 611 mass shootings, and 21 mass murders, according to the non-profit’s tabulations.

Gun Violence Archive listed the most recent mass murder as a murder-suicide that left five people dead in Arkansas on Christmas Day, a spree that claimed the lives of three children, the youngest of which was 7 years old. The most violent incidents of mass murder claimed seven lives each last year, with crimes to that degree reported three times; in March, June and September.

Overall, with all of its political unrest and racial injustice, 2020 was a deadly year for gun violence.

In July, a report from the Brookings Institution found that Americans set a gun-buying record with approximately 19 million firearms sold.

A worker restocks handguns at Davidson Defense in Orem, Utah, on March 20, 2020. AFP / GEORGE FREY