A man was killed as he and his wife tried to lock up their Gwinnett County business late Monday, police said.

Time Internet Café owners Andrew Shin and Soyoun Ahn were leaving just before midnight when an armed man wearing a dark hoodie and a white mask approached them and demanded money, Gwinnett police Cpl. Michele Pihera said.

Shin, 52, of Dunwoody, pulled out his own gun, and the two men began shooting at one another, Pihera said.

Ahn, who hid behind the couple’s BMW SUV during the exchange of gunfire, told police she saw her husband fall onto the sidewalk in front of their business. Shin died at the scene on Steve Reynolds Boulevard.

Ahn, 53, looked around the BMW and saw the masked man, identified by police as Diante Doby, “crawling toward a dark colored passenger car,” Pihera said.

The driver, Kendra Yvonne Gates, 22, of Stone Mountain, took Doby to a nearby McDonald’s on Pleasant Hill Road, called 911 and told dispatchers her boyfriend had been shot, Pihera said. Doby was pronounced dead in front of the McDonald’s.

Gates remained at the scene after calling 911 and was taken to Gwinnett police headquarters for an interview.

After that interview, police arrested her. She was in the Gwinnett jail Tuesday on a charge of armed robbery.