A fire that destroyed a building at the shuttered Lake Grove School on Friday afternoon was intentionally set, Suffolk police said.

The fire was reported at 3:43 p.m. and was still smoldering at night, forcing firefighters and emergency services officials to take steps to raze the structure, police said.

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No injuries were reported.

Police are asking for the public's help in finding whoever is responsible for the blaze.

A fire on Aug. 8 damaged a different building on the same property, according to police.

Lake Grove, which closed in June 2013 amid financial troubles, was a special education school and residential facility that served roughly 40 children.