Authorities have determined that a Des Moines woman, found dead in a burning apartment, did not die because of the fire. An autopsy report says 62-year-old Velva Schmitt died of "natural causes prior to ignition of the fire."

Des Moines Police Sergeant Vince Valdez says the cause of the fire is still under investigation, but it appears to be some sort of accident. "There’s no foul play or suspect circumstances surrounding this investigation of her death," Valdez said. Schmitt’s son, 39-year-old Merle Ervin, said he tried to put out the fire but was overcome by heat and smoke. He was treated for smoke inhalation.

The autopsy does not reveal exactly how his mother died. "Something happened before that fire even started," Valdez said. "(Schmitt died) of natural causes, but what those are…it’s unknown."

The fire was reported just after three o’clock Saturday morning at the Sunburst Apartments. No one else was seriously hurt, but six residents were left homeless.