General Discussion

https://www.icc-cpi.int/about/how-the-court-works

The ICC is intended to complement, not to replace, national criminal systems; it prosecutes cases only when States do not are unwilling or unable to do so genuinely.

As a judicial institution, the ICC does not have its own police force or enforcement body; thus, it relies on cooperation with countries worldwide for support, particularly for making arrests, transferring arrested persons to the ICC detention centre in The Hague, freezing suspects’ assets, and enforcing sentences.

While not a United Nations organization, the Court has a cooperation agreement with the United Nations. When a situation is not within the Court’s jurisdiction, the United Nations Security Council can refer the situation to the ICC granting it jurisdiction. This has been done in the situations in Darfur (Sudan) and Libya.

... Pre-Trial judges issue warrants of arrest and ensure there is enough evidence before a case can go to trial.