Iowa Code § 321.81: Presumptive evidence.

Whoever shall conceal, barter, sell, possess or dispose of any vehicle or component part which has been stolen, or shall disguise, alter, or change such vehicle or component part or the vehicle identification number or component part number thereof, or remove or change the registration plate thereon, or do any act designed to prevent identification of such vehicle or component part, shall be presumed to have knowledge that such vehicle or component part had been stolen.