Shannon Watts, the founder of Moms Demand Action for Gun Sense in America, cited a statistic that belies the sense that mass shootings are usually random: In more than half of all mass shootings in the United States from 2009 to 2017, an intimate partner or family member of the perpetrator was among the victims. The study, by the gun control advocacy group Everytown for Gun Safety, defined mass shootings as those in which four or more people died, not including the gunman. Federal law prohibits people convicted of certain domestic violence crimes, and some abusers who are subject to protective orders, from buying or owning guns.