PRIEST LAKE, Idaho -

Authorities confirm one person has died in a house fire at the McDonald Logging Company in Priest Lake.

The fire broke out Monday evening at the home, located along Highway 57 around milepost 27. Tuesday morning the Bonner County Sheriff's Office said it was searching for a 74-year-old woman who was missing after her home was destroyed by the fire.

By the afternoon they confirmed first responders had found a body in the rubble of the home.

Authorities say that Monday evening the husband and wife who lived on the property were doing everyday things when the fire broke out, she was doing laundry he was in the workshop.

"His signal to come in the house was when the lights go off in the office upstairs, he knows it time to come in for dinner so he saw the lights go out, came out and was approached by a passing motorist who said, 'Hey, your house is on fire,'" said Detective Sergeant Gary Johnston with the Bonner County Sheriff's Department.

The house had been upgraded throughout the years and the McDonald Logging Co. business office was built just off the main home.

"I think they've been married for 50 years and they've lived up here a large percentage of that time," Johnston said.

Three volunteer fire departments responded to the call, searching the office on arrival.

"The place was fully engulfed and falling in on itself," said Johnston.

But the home was too far gone to go inside. Crews tried to contain the blaze and save what they could of the surrounding structures.

"Sub-station right on the other side of the fence behind me and if that would have went the power for the entire Priest Lake, this side of Priest Lake would have went, so I'm told," Johnston said.

The cause of the fire is under investigation.

"A lot of different possible causes and with the house falling in on itself determining an origin is going to be really difficult as well," Johnston said.