WINTERPORT, Maine — A neighbor who lives next to a garage apartment on Monroe Road that caught fire Monday morning, noticed the blaze and called for assistance.

Josh Smith said his mother-in-law, who lives across the street from him and next door to the burned home, called him to say there was a fire.

“I ran up and nobody was there,” he said. “She said the neighbor’s trailer is on fire. I ran over and looked and it wasn’t the trailer, it was the barn. I think it was an apartment.

“At that point, the propane tanks had both burned off and the right side was completely engulfed,” Smith said. “The siding had melted off and black smoke was billowing out.”

Winterport Volunteer Fire Department got the call at around 11:25 a.m., Fire Chief Thomas Doe said.

“There was a lean-to addition on the side of a garage that had been converted into a home,” he said. “That, apparently, is where the source of the ignition was.”

The two-story home, which looks similar to a barn, sits back from the road in a field and is owned by Craig Cullins. An unoccupied trailer, which was not damaged, sits between the house and the road, the chief said.

“There is a lot of damage,” Doe said. By the time firefighters arrived, the fire “had made it into the roof structure. The lean-to portion is completely destroyed.”

Four walls remain, and “the fire damage is pretty much restricted to that wall next to that lean-to,” he said.

Investigators with the State Fire Marshal’s Office will determine how the fire began.

Crews from both Frankfort departments and Hampden assisted local firefighters, and no injuries were reported, Doe said. The last firefighter left the scene around 3 p.m.

The only occupant of the burning building did manage to escape the fire, Smith said.

“A cat ended up squeezing his way out,” he said.