MIDDLESEX TWP — The state police fire marshal's office will investigate a suspicious blaze early this morning that badly damaged a long-vacant home on Sandy Hill Road.

Flames were already shooting outside the two-story, wood-frame house by the time firefighters got there shortly after 3:30 a.m. A passing motorist saw the fire and called 911.

"We knew it was an abandoned structure," said Chief Andrew Huerbin of the Middlesex Township Volunteer Fire Company, "so we took up a defensive position."

Six fire departments responded, he said, largely because there are no hydrants in that rural part of the township just past Leslie Road.

In all, seven tankers were sent to the fire, which threatened no other homes or structures. No injuries were reported.

Fire crews said they were able to get a "good knockdown" and keep the home from burning to the ground. But the house has extensive damage and would have to be torn down.

Officials did not immediately know who owned the house, which has been abandoned for "quite a few years," Huerbin said.

He said he called for the fire marshal to investigate what could be a case of arson.

"You have an abandoned house with no utility hookups and a fire that started from the exterior of the building and a suspicious burn pattern," Huerbin said. "That's why the fire marshal's been called in."