Authorities say a police officer fatally shot an armed man early Monday after he had taken two people hostage at a gas station in an Atlanta suburb.

The Georgia Bureau of Investigation is investigating the shooting at a Marathon gas station and convenience store in Mableton, a community in greater Atlanta's Cobb County.

The Cobb County Department of Public Safety said police responded at 11:13 p.m. Sunday to a report of an armed robbery at the store and determined that two employees were being held inside at gunpoint by a man. The police department said it dispatched a SWAT team and crisis negotiators.

The GBI said that during a standoff, 18-year-old Demetrius Dorsey, of Atlanta, was shot by a SWAT officer early Monday morning. Dorsey was taken to a hospital where he later died. State authorities said preliminary information indicates that a handgun found at the scene belonged to Dorsey.

The two held hostage weren't injured, authorities added.

The Georgia Bureau of Investigation is conducting an independent review of the fatal shooting and the findings are to be turned over to the county district attorney's office.

Authorities didn't immediately disclose the race or races of the man and the SWAT officer.