WATERVILLE — A Wednesday night fire that destroyed a garage and damaged multiple vehicles on Belmont Avenue originated in the garage, but investigators are still working to identify its cause, according to the Office of the State Fire Marshal.

No one was injured in the 9 p.m. fire at 5 Belmont Ave., which was fought by about 30 firefighters, according to a news release from the Waterville fire department.

Sgt. Ken Grimes of the fire marshal’s office said Thursday that investigators were on scene and would conduct interviews into the evening and possibly on Friday to determine the cause.

Damage included the loss of the detached garage, a 2006 Dodge pickup truck and a boat. An antique half-ton military vehicle was damaged, and the fire melted vinyl siding on the house, which is about 15 feet from the detached garage.

All the occupants of the two-apartment building, owned by Robert Butcher, were safely evacuated, according to the release.

Deanna Butcher, who lives with her husband in the downstairs apartment, said Wednesday night that she believed the blaze’s origin was suspicious, but doesn’t know who would have set it.

Upstairs tenant Rick Mahew discovered the fire when he smelled burning plastic and looked out the window to see the garage in flames.

Butcher, 55, said once they saw the fire, it was already well underway. “As soon as we came outside we saw the boat, the truck, the garage — all of it — engulfed,” she said.

Others who saw the fire Wednesday night said it was preceded by what sounded like an explosion.

Belmont Avenue is off Western Avenue, near the Elm Street end. Traffic on Belmont and Western avenues was blocked off as the fire was fought.

Rachel Ohm — 612-2368

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Twitter: @rachel_ohm