OYSTER BAY - A historic home in Oyster Bay that dates back to the 1660s was gutted by a fire that has been deemed suspicious by police.

The flames broke out Saturday night at the Mill Pond House in Oyster Bay. It took about 100 firefighters nearly an hour to douse the blaze.

Investigators say the home was vacant, and they believe the fire was not accidental. News 12 Long Island has learned that it marks the second fire at the house in just a week.

Sources say that the fire hydrant closest to the house wasn't working. A hydrant down the road had to be used to extinguish the fire.

The Town of Oyster Bay purchased the Mill Pond House back in 2008 for $1.9 million. The five-bedroom, 334-year-old home is one of the oldest structures in Oyster Bay.

Deputy Town Supervisor Leonard Genova says Town Supervisor John Venditto had the home boarded up after the first fire, and extra patrols were placed near the house.

Genova says the town wanted to make significant improvements to restore the home, but the renovations would have been costly.

The town's building commissioner will examine the home on Monday to determine if it is salvageable.

Nassau County Fire Marshall and Arson-Bomb Squad detectives are investigating. They're asking anyone with information to call Crime Stoppers at 1-800-244-TIPS.