Fire investigators continue to search for a cause for Tuesday night's fatal fire in Conyers that claimed the life of four young children.

Investigators say there was not a single working smoke detector inside the home.

"We know that upstairs, there's no evidence of a smoke detector," said Rockdale County Fire and Rescue spokesman Michael Morris tell Channel 2 Action news.  "We did find one downstairs, however, it was inoperable."

Morris says the downstairs smoke detector did not have a battery inside, but officials could not tell if that was a violation of county code.

Investigators confirm the blaze appears to have started in an upstairs hallway near the bathroom.

Reba Glass, the mother of five, managed to toss her 6-year-old son Darnell Junior, out of a second story window and then jumped herself.

Officials say after rescuing her mother, Glass tried to rush back upstairs to her four other children, but suffered second and third degree burns over 40 percent of her body and wasn't able to save Ah'Dariya, 9, DeShawn, 7, Amoni, 3 and 8-month-old Deon Jr.

The blaze gutted the Pinedale Circle home.

Six-year-old Darnell, who survived, was treated and released from Children's Healthcare of Atlanta at Egleston, but Glass remains in Grady Hospital's burn unit.

"Lots of pain," said family pastor Billie Cox, describing Reba Glass' injuries.  "She has burns on both arms, her right leg, stomach, back and on her forehead."

Cox visited Glass in the hospital on Thursday morning.  She said Glass was in good spirits but was devastated by her loss.

"Emotionally? I think I'm going to say indescribable because I just can't even imagine being able to find a descriptive (word) that would categorize what she must be feeling at this moment," said Cox.

Cox held a prayer service for the family at the Macedonia Baptist Church in Conyers on Thursday night.

A memorial fund has been set up at Wells Fargo Bank and donations can be made in the name of the Glass family. A Facebook page is also soliciting donations.

Meanwhile, a funeral home in Conyers is offering free services for the four children who died in the house fire.

Representatives at the Gregory B. Levett and Sons Funeral Home say the funeral will be delayed until their mother is released from the hospital.