A grocery store cashier in the Atlanta area was killed and three other people were wounded Monday in a shooting that followed an argument over wearing face masks in the supermarket, authorities said.DeKalb County Sheriff Melody Maddox said the shooting occurred inside the Big Bear Supermarket in Decatur while several people were inside the business. She said a female cashier was killed when a man opened fire."There was some confrontation, argument — I'm not sure exactly what — in reference to the wearing of masks, at which time the subject pulled out a weapon and shot the cashier," Maddox said at a news conference. Maddox said she did not know the details of the argument.The customer was identified as Victor Lee Tucker, Jr., 30, of Palmetto, Georgia, according to the Georgia Bureau of Investigation. The agency said preliminary information indicates that Tucker got into an argument with the cashier and left the store without making his purchase, but he immediately returned inside."Tucker walked directly back to the cashier, pulled out a handgun and shot her," the Georgia Bureau of Investigation wrote in the news release.A reserve deputy, who was employed part-time for security with the store, exchanged fire with the suspect and both were wounded, the sheriff said. DeKalb County Police Department officers arrested Tucker as he was attempting to crawl out the front door of the supermarket, the Georgia Bureau of Investigation wrote in the statement.Maddox said the deputy was hit twice by gunfire but was wearing a bulletproof vest and was taken to a medical center where he was in stable condition. The Georgia Bureau of Investigation said Tucker is also in stable condition.The agency said a second cashier was grazed by a bullet. She was treated for her injury at the scene.The deputy is a retired deputy and member of a reserve unit. The unit consists of certified law enforcement officers not actively working for a law enforcement agency. Such deputies can work with a sheriff’s office on a volunteer basis and can work part time security jobs, the sheriff’s department said.Maddox said the deputy’s response might have kept other people from being hurt."That is what he is trained to do," Maddox said.The supermarket is located near The Gallery at South DeKalb mall but is not a tenant of that complex, authorities said.Decatur is a suburban community about 6 miles east of downtown Atlanta.