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
III. NOTIFICATION T O THE PROSECUTOR AND ACTION T O BE TAKEN UPON THE PROSECUTOR'S NOTIFICATION
Article 19
(3) If the criminal prosecution has been commenced in the Republic of Croatia, the Government of the Republic of Croatia may request the International Criminal Court to have the case concerned referred to it.
Admissibility challenge
Admissibility challenge - State investigation or prosecution
EDIT.