Attacks in Philadelphia and Chattanooga, Tennessee, may have involved multiple shooters, authorities said.
The U.S. had more mass shooting deaths in the first weekend of June than in the previous three-day weekend, which ended with Memorial Day.
The tally for weekend violence through Sunday night was at least 12 killed and at least 38 injured in mass shootings, defined by the Gun Violence Archive as incidents in which “four or more people are shot or killed, not including the shooter.”
During the holiday weekend, nine people were killed and more than 60 others were injured in attacks fitting that definition.
