NEWCOMERSTOWN, Ohio (AP) — Authorities investigating a fire that claimed the lives of six members of an Ohio family are looking at the possibility that the blaze was sparked by alternative methods of heating that the family was using to stay warm.

Ohio Fire Marshal Kevin Reardon said the blaze reported at 1:30 a.m. Monday in Newcomerstown resulted in “the tragic loss of an entire family” and came during a record year for fire deaths in the state.

Officials said arriving fire crews found heavy fire throughout the first-floor level that made entry unsafe, and the structure collapsed into the basement shortly after 2 a.m. Monday. Six victims were removed, the Tuscarawas County coroner’s office said. No details about them were released pending notification of relatives.

Brian Peterman, investigations assistant bureau chief for the state fire marshal’s office, said a wood burner, kerosene heaters and electrical space heaters were being used to heat the home, and he said the heating devices were “most likely not used in the proper manner.”

“With the below-zero weather, there was a family of six … they were trying to do whatever they could to stay warm,” he said. “Unfortunately, with those devices there are hazards that go along with that.”

No evidence of smoke detectors was immediately found, he said, but noted that damage to the structure was extensive. Officials believe the property was a rental and are trying to track down the owner and determine whether there was any insurance, he said.

The Newcomerstown Board of Education said grief support would be offered to “those affected by this devastating event.” Officials said “counselors, faith-based support as well as school staff” would be available Tuesday and additional counselors and support staff would also be available when students return Tuesday, Jan. 3,

“Our hearts are heavy as we begin to process the enormity of this loss,” Superintendent Jason Peoples said in a social media post.

Mayor Pat Cadle said crews from a number of areas were at the scene throughout the night and morning despite what he called “intense cold temperatures.” Cadle told reporters that the community was saddened by “this tragedy and loss of life.”

The fire was part of a deadly holiday weekend that saw 10 people killed in fires in Ohio. Officials say 151 people have perished in fires in the state this year. Many fires have involved smoking and careless disposal of cigarettes, smoking while on oxygen and use of heating devices.