CHATTANOOGA, (WRCB)  --  Chattanooga fire investigators are trying to figure out what started a fire that took the life of a woman Saturday morning.  It happened on Tall Timber Trail Road, where a man and his girlfriend awoke to smoke and flames.

The man made it out alive, tragically his girlfriend did not.  Fire officials say the home off Browntown Road is a total loss.

The man told officials he and his girlfriend were about to escape through a window when she ran down the hallway looking for their dog.   

"We woke up to a bunch of fire trucks," says neighbor Jim Yunge.  "We thought it might even be in the subdivision."

The fire wasn't in Yunge's subdivision, but it was nearby, on Tall Timber Trail Road.  "It's a sad story it really is," Yunge says. 

Chattanooga Fire Officials say the man and woman who live in the home awoke to a smoke filled house.

"They immediately got up," says Bruce Garner with the Chattanooga Fire Department.  "The smoke was already very intense."

Garner says that's when the couple began searching for an exit.  "He screamed at her to come his way," Garner says describing what happened.  "He saw was her running down the hallway to get the dog."

Garner says the man waited, still screaming for his girlfriend.  Eventually the heat became too intense.   

"He escaped through a window.  He kept yelling for his girlfriend," Garner says.  "She didn't answer."

The man ran to a neighbors home and called 911.  By the time firefighters arrived the house was fully engulfed.

"Around 9:00 a.m. firefighters found a body inside the house," Garner says.  "We believe it's the man's girlfriend."

Garner says the couple had been living in the house since May without running water or electricity.  They were using candles and flashlights for light.

"That certainly suggests something," Garner says.  "I must emphasize though, the cause of the fire is still under investigation."

Officials haven't released the victim's name.  Chattanooga Police Major Crimes Division investigators are assisting fire officials with the investigation.