Proprio motu investigation by the ICC Prosecutor

Under what circumstances can the Prosecutor initiate investigations proprio motu?

The independent ability of the Prosecutor to initiate his/her own investigations and cases was one of the most hotly debated issues during the negotiations of the Rome Statute of the International Criminal Court (“Rome Statute”). The results of these negotiations are now enshrined in Articles 13(c), 15 and 53(1) of the Rome Statute that regulate the circumstances under which such a power can be exercised at the International Criminal Court (“ICC”). These are briefly explained below.


First, the Prosecutor must conduct a preliminary examination of information received regarding alleged crime(s). He/she can request information from United Nations organs, States, NGOs and other reliable sources to aid in this process; Article 15(2). Only after the Prosecutor has analysed the seriousness of the information and concluded that there is a reasonable basis to commence an investigation, can a request be made to the Pre-Trial Chamber to launch an investigation. In making the request, the Prosecutor must present to the Pre-Trial Chamber information in his/her possession that supports the initiation of an investigation; Article 15(3).

Once an application has been filed, it falls upon the Judges of the Pre-Trial Chamber to evaluate the information presented by the Prosecutor. For the Judges to authorize an investigation, a number of requirements must be met.[1]

Reasonable basis standard

The applicable standard that the Prosecutor must meet for a successful application is that of a “reasonable basis to proceed”; Article 15(4). This is a relatively low evidentiary standard, in the sense that the information presented to the Chamber need not be conclusive and need not eliminate all other possible interpretations of the information. Instead, the Pre-Trial Chamber must be satisfied that a reasonable or sensible justification exists for the belief that a crime(s) within the ICC’s jurisdiction is being or has been committed.

Crimes falling within the jurisdiction of the ICC

The Pre-Trial Chamber must determine whether, on the information presented, it has jurisdiction over the alleged crimes. This means that the crime(s) in question should:

  1. Fall within either the definition of war crimes, crimes against humanity and/or genocide (jurisdiction ratione materiae);[2]
  2. Have been committed by a national of a State party (jurisdiction ratione personae) or on the territory of a State party (jurisdiction ratione loci);[3]
  3. Have been committed after 1 July 2002 or after the date upon which the Rome Statute entered into force for the aforementioned State (jurisdiction ratione temporis).[4]

Complementarity requirement

Pursuant to the principle of complementarity, the Pre-Trial Chamber must also examine whether any State(s) related to the Prosecutor’s application have conducted, or are conducting, national proceedings (in the form of investigations and/or prosecutions) in relation to the crimes alleged or the persons involved which would likely form the object of the Prosecutor’s investigations. If this is answered in the affirmative, then ­the application would be inadmissible unless the State is, or has been, unwilling or unable to carry out investigations and/or prosecutions; Article 17.

Gravity requirement

In addition, an application must demonstrate that the likely set of cases or potential cases arising from the Prosecution’s investigations are of sufficient gravity to justify ICC action. This involves an assessment of the groups of persons or individuals likely to form the object of the Prosecutor’s investigations, the nature of the crimes alleged and their modus operandi through a qualitative and quantitative approach.[5]

Interests of justice

According to ICC jurisprudence,[6] the Prosecutor is not required, under this element, to establish that an investigation is actually in the interests of justice. Rather, if the Prosecutor determines that an investigation would not be in the interests of justice, he/she must inform the Pre-Trial Chamber, which may then review the reasons for such a decision, taking into account the interests of the victims and the gravity of the alleged crimes; Article 53.

It is only when the Pre-Trial Chamber is satisfied of the aforementioned elements, that the Prosecutor can be authorized to commence proprio motu investigations.

This article was written by Manuel Ventura. He can be contacted at

[1] For a far more detailed examination of the requirements see Pre-Trial Chamber II, Decision Pursuant to Article 15 of the Rome Statute on the Authorization of an Investigation into the Situation in the Republic of Kenya, No. ICC-01/09-19-Corr, 31 March 2010, (“Kenya Investigation Authorization Decision”),paras. 17-69.

[2] The Court also has jurisdiction over the crime of aggression, but only after the recently agreed definition is ratified by 30 States Parties and when States Parties decide to activate the ICC’s jurisdiction with respect to the crime at any time after 1 January 2017.

[3] Notwithstanding, under Article 12(3) of the Rome Statute a State that is not a State Party can lodge a declaration accepting the ICC’s jurisdiction over alleged crimes committed on its territory or by its nationals.

[4]This date varies between States Parties, but it cannot be before 1 July 2002 (when the Rome Statute entered into force).

[5] See Kenya Investigation Authorization Decision, paras. 59-62.

[6] See Kenya Investigation Authorization Decision, para. 63.