(CNN) -- The suspected gunman in the slaying of five people inside a Greenwood County, South Carolina, home was a 27-year-old man who took his own life, too, authorities said.
Sheriff's deputies found the six bodies inside a house after two phone calls to 911.
Bryan Eugene Sweatt is suspected of having killed the five others before turning his gun on himself, Greenwood County Sheriff Tony Davis told reporters Wednesday.
The first call, which came just before 6 p.m. on Tuesday, was about an armed person threatening to harm himself, Davis said.
The call was cut off, and deputies began heading to the scene. A second call came in while they were en route, saying that some children who had left the house in question told neighbors that a man was holding hostages there.
Attempts to make contact with anyone inside were unsuccessful, and a SWAT team finally entered the premises. They found the bodies of four adults and two children inside.
The victims were identified as Richard Allen Fields, 51; Melissa Maroney Fields, 49; Chandra Marie Fields, 26; Tariq Kenyon Robinson, 11; and William Asa Robinson, 9.
The suspect, Sweatt, was Chandra Fields' boyfriend, Davis said.
Richard and Melissa Fields were Chandra's parents, and the two boys were her nephews.
The investigation is ongoing, but it appears to have stemmed from a domestic violence incident, the sheriff said.
Investigators worked the crime scene until the sun rose Wednesday.
Sweatt and Chandra Fields had a 7-month-old baby, who was sent to a neighbor's house along with three other children before the incident, the sheriff said.
About 80 miles west of the state capital of Columbia, Greenwood County has roughly 70,000 people, according to the U.S. Census Bureau.