LAW on the Implementation of the Statute of the International Criminal Court and the Prosecution of Crimes against International Law of War and Humanitarian Law
V COOPERATION WITH INTERNATIONAL CRIMINAL COURT
Article 23
(4) The competent government bodies shall also undertake the activities which the International Criminal Court has not expressly requested, if it appears that they are necessary in order to find the perpetrator and collect evidence for a trial before the International Criminal Court.
Other types of assistance - authority - ICC proceedings
Other types of assistance - national procedures for ICC proceedings
EDIT.