28 C.F.R. § 0.64-4
The Assistant Attorney General, Criminal Division, in consultation with the Assistant Attorney General for National Security in matters related to the National Security Division's activities, is authorized to exercise all of the power and authority vested in the Attorney General under 18 U.S.C. 3508 that has not been delegated to the Director of the United States Marshals Service under 28 CFR 0.111a , including specifically the authority to determine whether and under what circumstances temporary transfer of a prisoner-witness to the United States is appropriate or inappropriate; to determine the point at which the witness should be returned to the transferring country; and to enter into appropriate agreements with the transferring country regarding the terms and conditions of the transfer. The Assistant Attorney General, Criminal Division is authorized to redelegate this authority within the Criminal Division to the Deputy Assistant Attorneys General and to the Director and Deputy Directors of the Office of International Affairs.
28 C.F.R. §0.64-4