Bartholomew County Sheriff Mark Gorbett said three men were found dead in the living room Saturday evening and a woman's body was found in a bedroom of the home in Waynesville, a small unincorporated town about 50 miles south of Indianapolis.
All four were shot to death, County Coroner Larry Fisher said.
"We still have crime scene techs and criminal investigators at the scene and anticipate them being there for quite a length of time," Gorbett said. "We are following up on all leads at this point and we have no one in custody at this time."
Fisher identified the woman as homeowner Katheryn Burton, who was 53 or 54, and two of the men as Aaron Cross and Thomas Smith, both around 40 years old. He withheld the name of the other man until relatives could be notified.
Gorbett said the man who returned home from work about 10:45 p.m. Saturday told authorities he lived at the house with his mother and stepfather. Authorities did not identify him.
Gorbett, returning to the scene Sunday morning and asked by reporters if he could provide any additional information, said, "Quadruple homicide."
The Rev. Gary Carroll, pastor at Waynesville Chapel Mercy Missionary Baptist Church about a half-block from the home, told The (Columbus, Ind.) Republic that he had no indication there had been trouble at the home until he saw the flashing lights Saturday night.
Carroll, who lives next door to the church, said he knew the residents of the home only in passing - enough to wave when he saw them. He said they seemed like nice people.
Beverly Nichols told the newspaper she mowed the grass for a friend directly across the street from home on Saturday afternoon and didn't notice anything out of the ordinary.
In September 1998, victims of another quadruple homicide were found outside of Waynesville in shallow graves beside the East Fork of the White River. Robert J. Bassett Jr. was convicted in July 2001 of killing a young mother, her two children and a 12-year-old family friend.