Dunn County (WQOW) - The state fire marshall's office has concluded its investigation of a fatal fire in Dunn County.
Vue Lor, 53, died of smoke inhalation in a house fire Sunday afternoon in Spring Brook.
Dunn County Sheriff Kevin Bygd told News 18 five other people were able to make it out with minor injuries.
On Thursday, Bygd told News 18 the fire marshall is ruling the cause of the fire 'undetermined.' Bygd said it is believed the fire started by a lit cigarette but the investigation was unable to prove the theory.