PARK FOREST, Ill. (CBS) — Officials believe careless use of smoking materials is what caused a fire that killed a mother and son in south suburban Park Forest Tuesday.

The Cook County Medical Examiner’s Office identifies the victims as 78-year old Julia Markeo ,and her 59-year old son, Darrell Nelson.

Park Forest Deputy Fire Chief Bruce Ziegle says it is believed the fire began when Julia Markeo fell asleep while smoking on a living room couch.

Ziegle says firefighters were called to 81 Ash St. in Gurnee shortly after 2 p.m. Tuesday. He says the fire was put out shortly after firefighters arrived.

Autopsies were scheduled for Wednesday. Ziegle says smoke inhalation is believed to have been the cause of death.

He says the State Fire Marshal’s Office has determined, preliminarily, that the cause of the fire was careless use of smoking materials.

Deputy Chief Ziegle says the fire was mainly contained to the living room.

LISTEN: WBBM Newsradio’s Bernie Tafoya reports

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