CLINTON TWP, Venango County — A fire that leveled a two-story barn proved much more damaging than authorities first believed.

The blaze that began just before midnight Monday not only razed the wooden barn built more than a century ago, it destroyed four vintage vehicles on the upper floor.

“They were antique cars,” said Trooper Ken Hamilton, a deputy fire marshal who is investigating the fire. He estimated the damage at $100,000.

Fire officials initially reported only one vehicle was inside the barn on Donaldson Road, north of Route 208. Investigators on Tuesday learned about the additional contents that also included two dirt bikes.

Among the classic cars gutted in the fire, Hamilton said, were a 1964 Ford and a 1975 Dodge. He did not immediately know the specific models.

While the cause of the fire will likely never be known, due to the extent of the damage, the trooper acknowledged, it is not considered suspicious.

Authorities suspect the barn, which had a basement, was built around 1900. It recently had undergone a renovation and had utilities connected to it.

Hamilton declined to identify the owner, who lives in Sewickley, Allegheny County. The property was believed to be insured.

The barn sat about 50 yards from a house that the same man owns.

“It was their summer cottage house,” Hamilton said, referring to the owner and his wife.

A neighbor first reported the fire to the county’s 911 center at 11:59 p.m. Monday. But by the time fire crews got to the barn, about seven miles north of the Butler County line, it was nearly on the ground.

Among the nine departments that helped battle the blaze were Harrisville, Marion Township and Eau Claire in Butler County.

Hamilton on Tuesday conducted an exterior inspection, but he had to keep his distance from the still-smoldering remains of the barn.

He said he planned to sift through the rubble once the heavy timber stops burning.