According to the DailyMail:
A cashier was shot dead and an off-duty deputy was wounded after a male customer pulled out a gun and opened fire when told he had to pull up his face mask in a Georgia grocery store on Monday.
Victor Lee Tucker Jr., of Palmetto, Georgia, had got into an argument with staff at the Big Bear grocery store in DeKalb County, on Monday over their store’s mask policy.
The 30-year-old appeared to leave after the argument, but returned moments later, holding a handgun, according to the Georgia Bureau of Investigation.
Tucker hit the casher, killing her, before he was shot and injured by an off-duty officer, a 30-year veteran of the DeKalb County Police Department, who was working as a security guard.
DeKalb County Sheriff Melody Maddox said Tucker managed to fire back twice, hitting the off-duty cop both times.-DailyMail.co.UK (June 14, 2021)
Masks are not mandated by the governor in Georgia, though companies have the option to require them.
According to Mugshots.com, Tucker faced charges for misdemeanor battery in 2012, driving with a suspended/revoked license in 2011 and 2015, obstruction of officers in 2007, and possession of a weapon on school property in 2008.