CHAPTER IV: OTHER FORMS OF COOPERATION
SECTION I: CONDITIONS
Art. 30 Forms of cooperation
Cooperation according to this chapter may include any procedural acts not prohibited by Swiss law that facilitate the investigation and prosecution of crimes within the jurisdiction of the Court or that serve to produce the proceeds of such crimes, in particular:
c. the questioning of any person being investigated or prosecuted
Questioning of persons - national procedures for ICC proceedings
Examination of witnesses - national procedures for ICC proceedings
EDIT.