28 CFR 571.53 - Determination of indigency by U.S. Magistrate - inmates in federal institutions.
(a) An inmate with a committed fine, or fine and costs who is imprisoned in a federal institution may make application for a determination of indigency directly to the U.S. Magistrate Judge in the district where the inmate is imprisoned under 18 U.S.C. 3569.
(c) If the U.S. Magistrate Judge finds that the inmate is indigent, the U.S. Magistrate Judge will administer the oath to the inmate. The inmate shall be released no earlier than the regularly established release date.
(d) If the U.S. Magistrate Judge finds that the inmate is not indigent, Bureau staff shall forward a referral package to the appropriate United States Attorney for a final determination as to the inmate's ability to pay the committed fine, or fine and costs.