Authorities arrived at the Douglasville subdivision of two-story homes, about 20 miles west of Atlanta, after receiving a 911 call around 3 p.m., Douglas County Sheriff's Lt. Glenn Daniel said.
The shooter, whose name has not been released, is believed to have died by a self-inflicted gunshot wound, Daniel said.
"I've been in law enforcement out here 20 years and this is the worst I've ever seen," Daniel said.
Investigators have not released the names of the suspect or the victims because their family members have not yet been notified. The motive of the shooting was not immediately clear.
Kenya Beyah, who lives about four doors down from the home where the shooting began, left flowers at the scene Saturday evening. She didn't know the family but said she saw kids playing outside from time to time, she said.