Frances Crutchfield died in the 200 block of North El Camino Real shortly after 1 a.m. Monday, according to the San Diego County Medical Examiner's Office.
About 20 minutes earlier, Crutchfield's great nephew awoke to the smell of smoke in the family's mobile home and crawled out of a bedroom window before calling 911, the Medical Examiner's Office reported.
Firefighters entered the home and found Crutchfield unresponsive in the home's master bathroom. She was brought outside and pronounced dead at the scene at 1:12 a.m., according to the M.E.
Preliminary evidence suggested that the blaze was sparked by a cigarette the woman was smoking in bed, according to Oceanside police.