DORMONT Authorities are investigating the cause of a fire that killed an elderly woman and critically injured her daughter.

Firefighters say 81-year-old Ruth DeSimone fell from her second-story Dormont apartment, her clothes ablaze, as firefighters tried to rescue her Sunday morning. She was pronounced dead at a hospital later in the afternoon.

Her daughter, 54-year-old Diane Koerbel, who jumped from the building as her clothes also were on fire, was hospitalized in critical condition.

Allegheny County Chief Deputy Fire Marshal Donald A. Brucker says the fire started in the women's living room at around 6 a.m. and doesn't appear to be suspicious.

Brucker says DeSimone tried to reach out to a firefighter on a ladder when she fell to the ground.