In a stunning twist to a tragic story, Rockdale County investigators now believe the 6-year-old survivor set the fire that killed his older sister and three brothers and seriously injured his mother earlier ths week.

Law enforcement officials made the announcement at an evening news conference Friday. Investigators believe the boy was playing with a lighter before the fire.

Rockdale County Fire Chief Dan Morgan said he will not be prosecuted because of his age, but will be referred for counseling.

“This is a tragic event and we have to make sure this six-year-old get the help he needs,” Morgan said.

He said that they have had preliminary discussions with the Rockdale County district attorney.

“It’s his belief that this six-year-old, and any six-year-old, cannot form the criminal intent to be prosecuted in Juvenile Court,” Morgan said.

The fire chief said the youth is believed to be with relatives in the Conyers area.

“We’re limited in what we can say because the child is a juvenile,” he said.

Morgan said investigators’ case notes will be turned over the Department of Family and Children Services for possible counseling and treatment.

The mother, Reeba Glass, is still hospitalized with severe burns over 40 percent of her body, including her forehead, stomach, arms, back and legs.

Flames erupted late Tuesday night on the second floor of the family’s duplex at 1149 Pinedale Circle in Conyers.

Glass managed to toss the 6-year-old out a window to safety, but suffered severe burns while trying to reach her four other children, Ah’Dariya Glass, 9, Dar;Shawn Glass, 7, Armoni Roberts, 3, and 8-month-old Deon Glass. They were sleeping in an upstairs bedroom and all perished in the fire.

Reeba Glass’ mother, Rosetta Mitchell, who was sleeping downstairs, escaped unharmed.

Morgan said investigators interviewed “several family members numerous times this week, including the three survivors. The interviews support the findings of the investigation. Lab results show no accelerants were found in the samples submitted and all accidental causes have been eliminated.”

Earlier, the chief said the home’s only smoke detector wasn’t working because it didn’t have a battery.

The family lost everything in the fire. Its church, Macedonia Baptist in Conyers, is collecting emergency clothing, shoes and household goods for the family, and a Glass Family Fund has been established at Wells Fargo bank. Donations can be made to account number 1009683226 at any branch of the bank.

A memorial service is being planned for Jan. 19 at Macedonia Baptist, 1052 Barton St., for the four children who died.