Gwinnett County authorities are still trying to determine the cause of a fire that killed a woman in her Norcross home Saturday night.

According to family, the woman was a chain smoker, which is consistent with evidence found at the scene, Gwinnett fire spokesman Capt. Tommy Rutledge said in a news release today. Investigators are waiting on lab results before making a final determination on the cause of the fire, he said. No foul play is suspected.

The incident happened in the 800 block of Heritage Valley Road.

Rutledge previously said the woman was discovered Saturday night by her son, who drove 17 hours to check on her when she did not answer phone calls. He said it appeared the fire had extinguished itself hours before anyone arrived at the house.

“Everything seemed normal when I came through earlier today,” neighbor Quincy Wilson told Channel 2 Action News. “That’s very shocking. I didn’t see any smoke. I didn’t see anything.”

The woman has been identified as 53-year-old Heather Ferguson, Channel 2 reported. Fire officials said the fire was contained to the second-floor bedroom where she was found and did not spread to the rest of the house.

“It’s not something you see often, but it is common that fires will burn the oxygen in a certain room and be contained to that room,” Rutledge said.

—Angel K. Brooks contributed to this report.