A Glynn County grand jury on Monday indicted Guy Heinze Jr. on eight counts of malice murder, one count of attempted murder and two drug possession charges.
District Attorney Stephen Kelley said the Aug. 29 slayings easily met the requirements to seek a death sentence.
"When I first heard there were eight people killed, this a was potential capital case," Kelley told reporters.
The indictment charging Heinze said all of the victims died from blows to the head, but otherwise offered no new information on the killings. Police said last week they believe Heinze alone beat each of the victims to death with a blunt weapon.
Kelley refused to comment when asked if he felt confident Heinze was the only killer. Relatives of Heinze and the victims said they found that difficult to believe.
"How could one man beat all those people and nobody defend themselves? That doesn't make any sense," said William Heinze, the suspect's grandfather. "Plus the fact that he lived there and loved those people. My son and him were more like brothers than father and son."
Authorities have released few other details about the brutal attack, including a possible motive, saying they don't want to reveal anything that could jeopardize the case.
The dead included the suspect's father, 45-year-old Guy Heinze Sr., and six members of an extended family the Heinzes lived with in a 980-square-foot mobile home just north of the port city of Brunswick, midway between Savannah and Jacksonville, Fla.
Also killed were Rusty Toler Sr., 44; his sister Brenda Gail Falagan, 49; and Toler's four children: Chrissy, 22; Russell Jr., 20; Michael, 19; and Michelle, 15.
Chrissy Toler's boyfriend, 30-year-old Joseph L. West, was also killed. Her 3-year-old son, Byron Jimerson Jr., survived the attack with serious injuries.
Heinze remained jailed Monday. His attorney, Ron Harrison, was not at his Brunswick office and did not immediately return a message seeking comment. He has said previously that Heinze didn't kill anyone and was distraught over the deaths.
Carl Rowe, an uncle of the four Toler children, said he and other relatives think Heinze deserves to die if he's convicted.
"They were kinda hoping for the death penalty," Rowe said. "I can't see of any reason, if he's guilty, that he should live."
Rowe said he trusts that police had enough evidence to charge Heinze with the slayings, but still can't believe he could have killed so many people by himself.
"I cannot believe one man could do this to eight people, especially a father that would give his life to save his kids," he said.