Upon a final decision by the courts of the United States that the transfer of the offender to the United States was not in accordance with the treaty or the laws of the United States and ordering the offender released from serving the sentence in the United States the offender may be returned to the country from which he was transferred to complete the sentence if the country in which the sentence was imposed requests his return. The Attorney General shall notify the appropriate authority of the country which imposed the sentence, within ten days, of a final decision of a court of the United States ordering the offender released. The notification shall specify the time within which the sentencing country must request the return of the offender which shall be no longer than thirty days.