The tax on distilled spirits withdrawn without payment of tax under this part and which are lost during transportation from the bonded premises of the distilled spirits plant from which withdrawn to (a) the port of export, (b) the manufacturing bonded warehouse, (c) the vessel or aircraft, (d) the foreign-trade zone, or (e) the customs bonded warehouse, as the case may be, may be remitted if evidence satisfactory to the appropriate TTB officer establishes that such distilled spirits have not been unlawfully diverted, or lost by theft with connivance, collusion, fraud, or negligence on the part of the exporter, owner, consignor, consignee, bailee, or carrier or the employees or agents of any of them: Provided, That such remission in the case of loss of distilled spirits by theft shall only be allowed to the extent that the claimant is not indemnified against or recompensed in respect of the tax for such loss.