Greenwood County Sheriff Tony Davis identified the gunman as 27-year-old Bryan Sweatt. Davis says Sweatt had dated one of the women who was killed and had a child with her.
Davis says the victims include the woman, her parents and two children. The sheriff says the shootings looked like executions.
Davis says Sweatt and the woman were in a custody dispute about their infant child. Davis believes Sweatt broke into the home and was waiting for the victims to come back.
Greenwood County Sheriff's Office spokesman John Long said the ages of the dead ranged from 9 years old to early 50s.