Authorities believe a 66-year-old woman who lived alone was the victim of a fatal house fire in Green Lake County.

But sheriff's officials said the remains have not yet been positively identified.

Firefighters responded to a house engulfed in flames in the Township of Princeton around 4 a.m. Tuesday. While firefighters battled the blaze, crews found a body.

WLUK-TV reported an autopsy conducted Tuesday found that the victim died of fire- and heat-related causes.

Authorities are still investigating the cause of the fire.