The firefighter claimed that he discovered the fire when he drove past the school at three in the morning last Saturday.
Dustin Shane Gerth, of Narvon, is accused of breaking into the Pleasant Valley School, arson, conspiracy, vandalism and corruption of minors. Police say two boys are under investigation for allegedly helping him.
Gerth's arrest affidavit says he confessed.
Gerth had claimed a friend in his car called 9-1-1 they raced to the Farmersville Fire Department. He then drove a fire engine to the scene to battle the fire.
The fire was extinguished in about 15 minutes but did 20-thousand dollars in damage. The school serves Amish and Old Order Mennonite children.