They arrested Michael Mitchell and his son, also named Michael Mitchell. They also took a juvenile into custody.
The fire happened at the Executive Storage Units on Old State Road 67. A witness told police they saw people fleeing the scene.
Knox County Sheriff Mike Morris and several deputies were able to track the Mitchell's down near Westport, Illinois.
Both Mitchells are being held in the Lawrence County Jail in Illinois. They face several charges including arson and burglary.