(Image Credit: KOMO/ABC News)

Velma Kellen thought her furnace was broken, and got the shock of her life when a repairman told her a squatter had been living under her house and stealing her heat.

"I said, 'You've got to be kidding me!'" Kellen, 73, told ABCNews.com.

For months, there were mysterious signs - an unlatched gate and the inexplicable odor of smoke inside Kellen's three-bedroom home in Yelm, Wash., about an hour's drive south of Seattle.

"It was worse than cigarettes," Kellen said.

Kellen, a retired caregiver, said her home was cold before Christmas, so she bought a new furnace, but still had the problem.

"I thought, 'This wasn't right,'" Kellen said. "It was rather cold in the front part of the house, so I called the furnace company and the repairman came to the house. "

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The repairman went outside for a few minutes to assess the problem and came back carrying an empty beer can he found under the house.

"He said, 'You've had people living under your house. They cut your ducts,'" Kellen said.

Kellen's three dogs were also fooled and never barked to alert her to the presence of an intruder, she said. Police have been unable to find whoever might have been living under the house.

Kellen, who has lived in Yelm for 13 years, said she now has quite a story to tell.

"It was something I never expected," she said.