Investigators say it -was- arson that’s responsible for the latest fire at Heritage Park of North Iowa in Forest City — a museum dedicated to preserving agricultural history. An arsonist apparently cut through a chain-link fence along the farm history museum grounds and set fire to a double corn crib that dated back to 1926. Volunteers have spent hundreds of hours collecting antique farm tools, building a staircase and refurbishing the second floor as a lookout tower. This is the second act of arson at the museum in the past year. The August 6th fire destroyed the Timberland Museum which housed historical artifacts.