DES PLAINES (CBS) — Fire investigators continued to work Tuesday morning to determine the cause of a fire that killed a woman early Monday at a home in northwest suburban Des Plaines.

Des Plaines Fire Chief Randy Trost said investigators had ruled out mechanical systems in the house as the cause of the fire, but had not determined the exact cause of the blaze that started in a basement bedroom.

Firefighters responded shortly after midnight to the report of a fire in the 1000 block of Irwin Avenue, according to Des Plaines Fire Chief Alan Wax.

When crews arrived on scene they found a split-level home “totally engulfed,” Wax said.

Homeowner Ronald Kauke told police officers that his daughter was still inside the house, according to a release from Des Plaines police.

Firefighters had the flames under control in about 20 minutes.

Kauke’s daughter was found dead in the family room, police said.

Sandra Lupi, 49, of the 1000 block of Irwin Avenue, was dead on the scene, according to the Cook County Medical Examiner’s office.

An adult man and a police officer were treated for smoke inhalation on the scene, the chief said.

Des Plaines police confirmed the officer had gone into the house to attempt a rescue and that he was not hospitalized.