Police have issued a countywide lookout for a suspect in a fatal shooting at a home in suburban Atlanta.

All available manpower is being used in south DeKalb County to find Julian Ardarrell Walker, wanted in connection with the shooting death of a man believed to be the stepfather of Walker's teenage girlfriend.

The young woman, who is in her late teens, had met Walker, who is in his 30s, while working at a pizza restaurant but apparently tried to break up with him.

Walker is believed to be driving a tan GMC truck with an extended cab. He stands 5-foot-10 and weighs 160 pounds, WAGA-TV reports.

The man may be responsible for the later shooting death of a woman in DeKalb County, police said.

The Associated Press contributed to this report.