Article 585.
4) summoning of persons staying abroad to make a personal voluntary appearance before the court or state prosecutor, in order to be examined as a witness or to be submitted to confrontation, and bringing persons under detention, for the same purposes, and
1. States Parties shall, in accordance with the provisions of this Part and under procedures of national law, comply with requests by the Court to provide the following assistance in relation to investigations or prosecutions:
(e) Facilitating the voluntary appearance of persons as witnesses or experts before the Court;