It can depend on who is telling the story, but this looks credible to me.
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"Importantly, the Mother Jones figures define mass shootings as public attacks in which the shooter and victims were generally unknown to each other, and four or more people were killed. Unlike the FBI’s “active shooting incidents,” where gangs and drugs are frequently involved, Mother Jonesexcludes all multiple murders related to drugs, gangs or domestic violence. They do include mass shootings by jihadist terrorists, however, which accounted for only 4 of their 98 incidents by my count.
The Mother Jones writers claim that “A recent analysis of this [Mother Jones] database by researchers at Harvard University, further corroborated by a recent FBI study, determined that mass shootings have been on the rise.”
https://www.cato.org/blog/are-mass-shootings-becoming-more-frequent