Investigators found the bodies of six people ranging in age from 9 to 51 when they responded Tuesday to a call from a man who said he was thinking about hurting himself.
Greenwood County Sheriff Tony Davis identified the man who fired the shots as 27-year-old Bryan Sweatt. Davis said Sweatt felt that the woman he had dated wasn't allowing him to see their infant child often enough. The infant was not among the dead.
Investigators believe Sweatt broke into the home and waited for the victims to return, Davis said, adding that the shootings looked like executions.
SWAT team members who entered the house found the bodies in three different rooms.
Sweatt had a long criminal record and was supposed to be in court Tuesday on a burglary charge, Davis said. The sheriff didn't have many details about the hearing, but said Sweatt faced up to 30 years if he was convicted.
In the morning, yellow police tape surrounded the one-story home on a rural stretch of road south of Greenwood, a city of about 23,000 in northwestern South Carolina.
Officers first went to the home in Greenwood County after receiving a call from a man who said he was thinking about hurting himself, authorities said. Davis said while police were on their way, a neighbor called 911 saying four children from that address had arrived at her house and told her a shot had been fired. He said the children remained at her house.
After about an hour and "several unsuccessful attempts" by officers to make contact with anyone in the home, the SWAT team entered and discovered the bodies, authorities said.