Investigators believe someone broke into the Ohio Chapel United Methodist Church in Columbus late Friday night or early Saturday morning.
Officials say the deadly Dec. 24 fire has been determined to be arson, but the investigation is ongoing.
The Leavenworth volunteer firefighter has been linked to arsons including one in March on Hoosier National Forest property.
A former Opry employee and witness for the prosecution said the defendant James Bowyer acted erratically the night of the fire.
A probable cause affidavit says extensive gambling losses may have led to the alleged arson.
It took more than a year to get ticketholders their money back following a suspicious fire at the Little Nashville Opry.
The owners were not owed the money because they failed to maintain the sprinkler system required by a contract with Indiana Insurance Company.