A summons or a warrant shall be issued by the justice, judge or magistrate judge ordering the offender to appear or to be brought before the issuing authority. If the justice, judge, or magistrate judge finds that the person before him is the offender described in the complaint and that the facts alleged in the complaint are true, he shall issue a warrant for commitment of the offender to the custody of the Attorney General until surrender shall be made. The findings and a copy of all the testimony taken before him and of all documents introduced before him shall be transmitted to the Secretary of State, that a Return Warrant may issue upon the requisition of the proper authorities of the sentencing country, for the surrender of offender.
18 U.S. Code § 4114 - Return of transferred offenders
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.
Upon receiving a request from the sentencing country that the offender ordered released be returned for the completion of his sentence, the Attorney General may file a complaint for the return of the offender with any justice or judge of the United States or any authorized magistrate judge within whose jurisdiction the offender is found. The complaint shall be upon oath and supported by affidavits establishing that the offender was convicted and sentenced by the courts of the country to which his return is requested; the offender was transferred to the United States for the execution of his sentence; the offender was ordered released by a court of the United States before he had completed his sentence because the transfer of the offender was not in accordance with the treaty or the laws of the United States; and that the sentencing country has requested that he be returned for the completion of the sentence. There shall be attached to the complaint a copy of the sentence of the sentencing court and of the decision of the court which ordered the offender released.
A complaint referred to in subsection (b) must be filed within sixty days from the date on which the decision ordering the release of the offender becomes final.
An offender returned under this section shall be subject to the jurisdiction of the country to which he is returned for all purposes.
An offender whose return is sought pursuant to this section may be admitted to bail or be released on his own recognizance at any stage of the proceedings.