tucker left without buying anything only to return to the store moments later with a handgun. and then he shot the cashier, killing her. the georgia bureau of investigation said the two got into an argument over the mask. here's the store's earn speaking to a cnn affiliate wxia. >> he had a mask. she just very cautious person so she had asked him to pull up his mask. he refused. and walked out. came back in and did that. a kind, loving human being. we can't understand. there's nothing to understand. >> the store's security officer, a 30-year veteran of the police department exchanged gunfire with tucker and he was arrested as he tried to crawl out of the front door of the store. he and the sheriff's deputy were taken to the hospital and we're told remain in stable condition, according to authorities. the dekalb county police department is investigating this shooting. the georgia bureau of investigation has been asked to as well. we've seen plenty of debates