One of the key factors of successful court proceedings against war crimes perpetrators is the establishment of legal framework for regional co-operation, given the fact that victims, witnesses, perpetrators and scenes of the crimes are situated in the territories of different states. Regional co-operation is a prerequisite for the ICTY's referral of the cases to national courts.

In May 2004, the Ministry of Justice of the Republic of Serbia signed the Memorandum of Understanding with the OSCE Mission in Serbia and Montenegro. Throughout 2003, the OSCE elaborated the Support Strategy for Judiciary and Police Capacity Building in the Republic of Serbia. The principal intention of this Strategy is to facilitate regional co-operation, so as to enable the prosecution of persons responsible for war crimes in accordance with interanationally recognized standards.

The co-operation would involve free exchange of evidentiary material and information related to investigations and operational planning, assistance in collecting evidence and examination of witnesses, transfers of cases to those states which have access to the crimes perpetrators, etc. This would finally result in harmonization of judicial practice in the area of war crimes trials.

UN Mission to Kosovo (UNMIK)

On 11 November 2004, the War Crimes Prosecutor hosted the UNMIK judicial delegation headed by Jean-Christian Cady, the UNMIK Deputy Secretary General's Special Representative in charge of judiciary and police, and Thomas Monaghan, Head of the UNMIK Justice Department. In accordance with the agreement reached during the meeting, the Serbian judicial authorities will be allowed to examine witnesses residing in the KM territory, whereas their UNMIK colleagues will be authorized to do the same in the territory of the Republic of Serbia.

On several occasions, the UNMIK Police provided logistic support to members of the Serbian judiciary, specifically to a deputy prosecutor and an investigative judge as they visited Kosovo in order to examine Albanian witnesses.

The Offices of the Serbian War Crimes Prosecutor and UNMIK Prosecutor have been working together on Cut-Off Heads, a case addressing a 1999 war crime against a group of Yugoslav Army members doing their mandatory military service at the time. The youths were captured and subsequently beheaded by the special KLA unit known as Black Eagles. The perpetrators' whereabouts are in the KM territory, while all relevant witnesses are residing in Serbia proper. Interviews with those likely to assist in the clarification of this incident have been jointly conducted by the UNMIK investigative authorities and the Serbian deputy prosecutor in charge of the case. 

Regional Liaison Officers

Supported by the Netherlands Embassy to Serbia, the project Regional Liaison Officers is aimed at the improvement of cooperation between the national prosecution services and of their existing capacities. This project has been envisaged as part of the overall support offered by the Netherlands Government to the OWCP conference entitled THE PALIĆ PROCESS - Regional Cooperation: Achievements and Commitments, Ten Years Later, which was held from 01 to 03 December in Palić.

The project implementation, alongside the UN initiative for the creation of an ad hoc regional cooperation council based at the UN Office in Sarajevo, will add new impetus to the ongoing regional dialogue and encourage its further development.

Republic Of Crotia

In November 2004, the OSCE organized an expert meeting at Palić Lake. Focusing on the enhancement of interstate cooperation in war crimes cases, the event was attended by representatives of the judiciaries of Bosnia-Herzegovina, Croatia and Serbia-Montenegro. The meeting addressed the Draft Memorandum on Agreement, proposed by the Croatian State Prosecutor, intended to promote direct cooperation between the Offices of the Serbian Public Prosecutor and the War Crimes Prosecutor (OWCP) on one side, and the Office of the Croatian State Prosecutor on the other.

Cooperation of Serbia-Montenegro with the Republic of Croatia is regulated by the European Convention on Mutual Legal Assistance in Criminal Matters, which was ratified by the FRY Assembly in 2001. A document that further regulates this matter is the Agreement on Legal Assistance in Civil and Criminal Matters, signed by the FRY and the Republic of Croatia. However, the OWCP practice highlighted the need for a more efficient, strictly professional form of cooperation, which generated the idea of the creation of a relevant agreement.

The need for such an agreement was clearly perceived in the course of proceedings in Ovčara, a case addressing the war crime against prisoners of war, committed at Ovčara farm outside Vukovar in 1992. Conducted before the Serbian judicial authorities, witness examinations in relation to the Ovčara massacre were strongly assisted by the Croatian Prosecutor's Office.

On 05 February 2005, the Agreement on the Realization and Enhancement of Cooperation in Fighting All Forms of Grave Crime was signed between the Offices of the Serbian Republic's Public Prosecutor and War Crimes Prosecutor on one side, and the Office of the Croatian Stae Prosecutor on the other.

Among other matters, this Agreement regulates the procedures governing the exchange of information between the two states' Prosecutor's Offices regarding the criminal offences recognized as war crimes. Pursuant to the Agreement, the two states undertook to exchange data, reports, documents and information that should facilitate the clarification of war crimes cases. One example of effective cooperation between the two national judiciaries was the clarification of the war crime committed in Lora, the port outside Split in 1992. 

On 13 October 2006, the Serbian War Crimes Prosecutor and Croatian State Prosecutor signed the Agreement on Cooperation in Prosecuting Perpetrators of War Crimes, Crimes against Humanity and Genocide, which set out the procedures governing the exchange of evidence, documents and information meant to facilitate the investigation, proving and sanctioning of war crimes.

Bosnia-Herzegovina

On 1 July 2005, the Memorandum of Agreement on the Realization and Enhancement of Cooperation in Fighting all Forms of Grave Crime was concluded between the Offices of the Serbian Republic's Public Prosecutor and War Crimes Prosecutor on one side, and the Office of the BH Prosecutor on the other.

On 31 January 2013, the Offices of the Serbian War Crimes Prosecutor and BH Prosecutor concluded the Protocol on Cooperation in Prosecuting Perpetrators of War Crimes, Crimes against Humanity and Genocide.

The Protocol defines instruments for effective prosecution of war crimes suspects. Operating on a voluntary basis, this documents makes it possible for the two Prosecutor’s Offices to mutually refer evidence and information related war crimes cases.

The Protocol was signed at the seat of the European Commission in Brussels, in the presence of a number of international figures, including the following: Mr. Stefano Sannino, Director General for EU Enlargement; Mr. Pierre Mirel, EU Director for the Western Balkans; representatives of the OSCE Mission to Serbia; Mr. Stephen Rapp, U.S. Ambassador for War Crimes Issues; and representatives of the U.S.A. Embassy in Belgrade.