The district attorney general for the district in which the sale is to be made shall then determine the amount or amounts which the property should bring at a fair sale, and, if the district attorney general thinks it expedient to do so, shall, in person or by agent, bid the property in for the state of Tennessee at a sum that the district attorney general thinks the property is reasonably worth. The amount at which the property is purchased shall in no event exceed the amount of the forfeiture for the satisfaction of which execution has been issued and the sale held.