MT- Last week’s fatal explosion at a house near here was caused by a propane gas leak, Gallatin County Sheriff Jim Cashell said Tuesday.

Denise Tuohy, 53, was killed Thursday night after the explosion and a subsequent fire destroyed her home about two miles south of Big Sky.

Tuohy, vice president of finance at the Yellowstone Club and a former Bozeman School Board trustee, heated her home with propane gas, Cashell said.

Investigators didn’t know what ignited the gas, but didn’t suspect foul play, he said.

The home was insured, and the insurance company is investigating what caused the leak, said Mark Roemer of the Central Insurance Agency in Big Sky. He declined to release the name of the insurance company that held the policy on the house.

Northern Energy, which filled Tuohy’s propane tank, also was unable to determine how the home’s heating source malfunctioned, said Chris Bowers, Northern Energy’s Bozeman manager.