Investigators think a man who said he was attacked, tied up, and left in the burning apartment building he owns in Windham concocted an elaborate hoax. Investigators with the state Fire Marshal’s Office have not charged 66-year-old Donato Corsetti, but say in court papers they believe he set the fire himself to collect on an insurance policy. Corsetti, who also owns a market next door, told investigators he was showing an apartment to two men who jumped, him, tied him up and set the Dec. 7 fire. Corsetti told police an organized crime group from Rhode Island was trying to scare him. Investigators said he kept changing his story. Investigators say the apartment and Corsetti’s home had been foreclosed on. Corsetti refused comment when reached by The Portland Press Herald.