From The Atlantic:

After murders in the United States soared to more than 21,000 in 2020, researchers began searching for a definitive explanation why. Many factors may have contributed, such as a pandemic-driven loss of social programs and societal and policing changes after George Floyd’s murder. But one hypothesis is simpler, and perhaps has significant explanatory power: A massive increase in gun sales in early 2020 led to additional murders.

New data from the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) suggest that that indeed may have been the case. According to the data, newly purchased weapons found their way into crimes much more quickly and often last year than in prior years. That seems to point to a definitive conclusion—that new guns led to more murders—but the data set cannot prove that just yet.