Whenever any person interested in any vessel, vehicle, aircraft, merchandise, or baggage seized under the provisions of this chapter, or who has incurred, or is alleged to have incurred, any fine or penalty thereunder, files with the Secretary of the Treasury if under the customs laws, and with the Commandant of the Coast Guard or the Commissioner of U.S. Customs and Border Protection, as the case may be, if under the navigation laws, before the sale of such vessel, vehicle, aircraft, merchandise, or baggage a petition for the remission or mitigation of such fine, penalty, or forfeiture, the Secretary of the Treasury, the Commandant of the Coast Guard, or the Commissioner of U.S. Customs and Border Protection, if he finds that such fine, penalty, or forfeiture was incurred without willful negligence or without any intention on the part of the petitioner to defraud the revenue or to violate the law, or finds the existence of such mitigating circumstances as to justify the remission or mitigation of such fine, penalty, or forfeiture, may remit or mitigate the same upon such terms and conditions as he deems reasonable and just, or order discontinuance of any prosecution relating thereto. In order to enable him to ascertain the facts, the Secretary of the Treasury may issue a commission to any customs officer to take testimony upon such petition: Provided, That nothing in this section shall be construed to deprive any person of an award of compensation made before the filing of such petition.