They say the cause of that fire is undetermined.
The Foard County Sheriff's Office says the fire started around 3:30 a.m. October 19 on a deer lease in the northwest part of the county.
Sixty-two year-old Leon Crabtree, 31-year-old Vidal Mora, and six-year-old Jorge Mora, all from Burk, died in that fire.
The fire marshal's report states the fire's point of origin was located several feet in diameter around a large wood burning furnace in a trailer on the lease.
It states that fire was kept going during the day by using wood, paper, and diesel fuel.
Officials say the fire quickly grew in size and intensity because it came into contact with combustible materials like a five-gallon storage container full of diesel fuel.
They say they were unable to eliminate electrical problems as the cause of the fire because the trailer previously had electrical problems.
They also say one of the men who lost their life in the fire was a smoker and was known to put out his cigarettes inside the trailer.
The unattended wood burning furnace is listed as another possible cause of the blaze.
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