Two children are dead Saturday after being shot by their father, who then turned the gun on himself.
The man also shot the children's mother, who was his wife, and her stepfather, authorities said. Their injuries were not fatal.
Perry Police Chief George Potter said 36-year-old Michael Lee Hill shot his two sons, Michael Anthony Hill, 7, and Richard Lawrence Hill, 10, execution style shortly before 2:30 p.m. at the home of his estranged wife's parents.
Hill was at the home reportedly to pick up his sons for a visit.
"Instead of picking them up, he used a (9 mm semi-automatic) gun to kill his sons," Potter said.
The couple had been separated for an undetermined length of time.
Hill, a truck driver, came to the residence at 640 Pineridge St., shot the two boys, then shot his wife's stepfather, 64-year-old Andrew Hill, in the chest and chased his wife, 30-year-old Bonnie Jean Hill, out of the home before shooting her three times in the leg and back.
He then shot himself in the head.
Andrew Hill remained in critical condition at The Medical Center of Central Georgia late Saturday. Bonnie Hill was listed in stable condition at the hospital.
Potter said investigators had not located a suicide note or any other evidence indicating Hill's plans to carry out the shootings.
"We have not found any notes or anything like that," Potter said. "The investigation is still early. But this ... circumstantially, it appears it was a planned thing."
Potter could not confirm where the boys attended school.
Authorities had never responded to the Pineridge Street home, he said.
He was not able to confirm if there was a history of domestic violence between the couple or if authorities had ever responded to their previous residence.
Potter could not confirm if Hill had a history of mental illness. He did not have a criminal record.
Authorities continue to investigate the incident.
Potter called the killings "unthinkable."
"It's a horrible tragedy," Potter said. "There hasn't been a homicide in Perry in over nine years."