WINTHROP — A fire destroyed the inside of a five-bay garage and an apartment above it Saturday night but left the attached two-story house on Route 41 mostly unscathed.

The cause of the fire, which began in a garage bay converted into a workshop, is unknown, said Winthrop Fire Chief Dan Brooks.

The owners of the home and the tenants in the second-floor unit were home, but no one was in the garage or the apartment above it, Brooks said.

The fire was reported just before 11 p.m., and the Winthop and Monmouth fire departments responded to the blaze, which Brooks estimated lasted a couple of hours.

He said fire gutted the inside of the garage, but the owner was able to move two vehicles out of it. A third vehicle wasn’t removed or damaged by the fire, Brooks said.

The fire destroyed everything in the workshop, including a Harley-Davidson motorcycle. 

Brooks said chemicals such as paint thinner and lacquer were stored in the workshop. It also had an electric baseboard heater and a space heater.

The State Fire Marshal’s Office is expected to investigate the fire Tuesday. Brooks said his department doesn’t consider the fire to be suspicious.

He said the owners, occupying the first floor of the house, and second-floor tenants didn’t stay in the house after the fire; but they should be able to return to it shortly, as it sustained only minor water and smoke damage.