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How do you investigate a sitting head of state for crimes that are occurring in a territory where he controls both the police and the army? How do you investigate a conspiracy involving political, police and military leaders in three different countries? How do you send investigators to collect evidence in crime scenes that are located in the middle of a war, or a country that refuses to let them in? These are but a few of the major challenges the Tribunal’s Office of the Prosecutor faced in its efforts to investigate Slobodan Milošević for crimes committed in Bosnia and Herzegovina (1992-1995), Croatia (1991-1995) and Kosovo (1999).

Croatia and Bosnia and Herzegovina

The indictment against Slobodan Milošević for crimes committed in Croatia and Bosnia and Herzegovina was in many ways the product of investigations that began as soon as the Tribunal opened its doors in 1994. These investigations resulted in dozens of indictments against low, mid and high-level perpetrators who participated in what Prosecutors believe was Slobodan Milošević’s plan to expel non-Serbs from territories he claimed They would become the blocks with which the Prosecution built the indictments against Slobodan Milošević for crimes committed in Croatia and Bosnia and Herzegovina.

The Strategy

The Tribunal’s first Prosecutor, Richard Goldstone, adopted a so-called pyramid strategy to investigate the involvement of high-level leaders: the Prosecution would investigate crimes committed on the ground, identify the direct perpetrators, investigate the local leaders who they reported to, then the municipal and regional-level leaders, and on up to the highest level. If the Prosecution could not prove the crimes on the ground, the reasoning went, they would have nothing with which to charge the highest-level leaders.

When the Prosecution’s first staff began work in early 1994, they faced the challenge of investigating the massive number of crimes that had been committed in Croatia and Bosnia and Herzegovina, by all sides in the conflicts. In Bosnia, the war was ongoing and Tribunal investigators could not access the crime scenes.

The Prosecution’s budget and resources in its early days made this task doubly daunting. The Prosecution occupied only a couple of rooms in the building that would become the ICTY’s headquarters in The Hague. There were barely enough desks and chairs to seat the Prosecution’s first contingent of personnel that numbered some 30 prosecutors, investigators and support staff.

The Prosecution began by investigating crimes committed in the northwestern Bosnian municipality of Prijedor, the location of the most notorious detention camps in the war - Omarska, Keraterm, and Trnopolje. The Prosecution had inherited a wealth of information about crimes in Prijedor from the Commission of Experts, a UN body that preceded the Tribunal’s establishment. The Prosecution would find its first witnesses through the Commission of Experts’ materials.

Tribunal investigators traveled the world to interview survivors of crimes committed in Prijedor. For example, although some Omarska camp survivors were still in Bosnia and Herzegovina, others were in a number of countries all over Europe, and as far as North America and Malaysia. Based on these interviews, the Tribunal was able to issue indictments against some 30 accused for crimes committed in the Omarska and Keraterm camps, ranging from the camp commander to the guards and visitors who came to the camps to beat and kill prisoners. The Prosecution had laid the first block at the bottom of the pyramid that would eventually lead to Slobodan Milošević.

Over the next months, with investigations in a number of places along and near Bosnia’s eastern and northeastern border, including Vlasenica, Zvornik, Bijeljina, Bosanski Šamac, Višegrad, Foča and Brčko, the Prosecution laid further blocks at the pyramid's base. It filled out its investigations in northwestern Bosnia with investigations in Ključ, Sanski Most, Bosanski Novi, Banja Luka and Kotor Varoš.

In addition to producing a number of indictments against direct perpetrators, these investigations also started leading the Prosecution up the pyramid. For example, in relation to Prijedor, the Prosecution issued indictments against municipal leaders Milan Kovačević, Simo Drljača, and Milomir Stakić, and against regional leaders Radoslav Brdjanin, Momir Talić and Stojan Župljanin.

In 1995, the Tribunal also issued its first indictment against the highest-level Bosnian Serb leaders, President Radovan Karadžić and army Chief of the General Staff Ratko Mladić, for crimes committed throughout the areas it was investigating in Bosnia and Herzegovina. Indictments against other Bosnian Serb leaders, namely Momčilo Krajišnik and Biljana Plavšić would follow. All of them would later be named as Slobodan Milošević’s co-perpetrators for crimes committed in Bosnia and Herzegovina.

In addition to following the trail to Milošević through the Bosnian Serb leadership, the Prosecution found another route up the pyramid. Investigations against particular direct perpetrators, namely paramilitary leaders Željko Ražnatović, aka “Arkan,” and Milan Lukić, revealed that they had direct links to Serbia’s State Security Service within Serbia’s Interior Ministry. Further investigations revealed that Slobodan Milošević effectively controlled both the Interior Ministry and the State Security Service.

In Croatia, the Prosecution adopted a similar strategy, investigating crimes that occurred in the eastern Croatian town of Vukovar, the coastal city of Dubrovnik, and a number of villages along Croatia's eastern border in an area called the Krajina. Unlike with the Bosnia investigations which resulted in a number of indictments against direct perpetrators, for crimes committed against non-Serbs in Croatia, the Tribunal began by indicting figures closer to the top of the pyramid. The Tribunal indicted officers from the Yugoslav People’s Army (JNA), local Croatian Serb leaders, and later officials from the Republic of Serbia who were close to Slobodan Milošević.

The Crime Scenes

In Croatia, by the time the Tribunal was operational in 1994, the conflict was less intense than in Bosnia with largely frozen frontlines and limited clashes. Nonetheless, investigating its crime scenes, such as the mass grave containing some 200 Croatians killed by Serb forces at the Ovčara farm near Vukovar, presented serious challenges.

With the initialing of the Dayton Peace Agreement in November 1995, the Bosnian war effectively ended and the Tribunal’s Prosecution saw an opportunity to access the crime scenes that witnesses had described for them. However, although the bullets were no longer flying, the Prosecution nevertheless faced delicate challenges in conducting its investigations on the ground: many Bosnian Serb officials, whom the Prosecution was investigating for their involvement in crimes, continued to hold positions of power and deliberately obstructed the Tribunal.

The Prosecution’s first crime scene investigation in Bosnia and Herzegovina was in Prijedor in February 1996, nearly four years after crimes were committed there. Tribunal investigators planned on visiting the locations of the Omarska, Keraterm and Trnopolje detention camps, and villages in the municipality, such as Kozarac and Hambarine, where witnesses had described murders, destruction of houses and mosques, and deportation. Before beginning their site investigations, Tribunal investigators went to inform Prijedor’s then chief of police, Simo Drljača, that they would be operating in his area.

The Prosecution had not yet indicted Drljača, but he was already under investigation. He told Tribunal investigators that they would have to get the permission of Radovan Karadžić, then still the President of Republika Srpska and already wanted by the Tribunal for war crimes. Tribunal investigators told Drljača that the Dayton Peace Agreement gave them freedom of movement. Some 200 soldiers from the NATO-led Peace Implementation Force (IFOR) were there with Tribunal personnel to back up their claim. Drljača had no choice but to relent (he would be killed a year later in an operation to arrest him). IFOR, later renamed Stabilisation Force (SFOR), would provide security for Tribunal investigators in a host of operations over the next years.

When Tribunal investigators began their investigations in Prijedor, they were greatly disturbed by the destruction that they saw. In the Brdo area of the municipality, every single house had been totally destroyed. In Kozarac, they found remnants of buildings, including the mosque, which had a circle with a cross through it. Investigation revealed that this was the sign that the building was a Muslim home and was to be destroyed. The Orthodox church, although surrounded by buildings that were totally destroyed, did not have a single mark on it. Everywhere the Tribunal investigators went throughout Prijedor during the 16 days that they spent on their first investigation there they found exactly the same type of destruction wherever Muslims or Bosnian Croats had resided.

When Tribunal investigators first entered the buildings in the Omarska iron ore mine that had served as a detention camp during the war, they found it in horrible condition; filthy and with toilets overflowing and blocked sewers. In their search for evidence of murders that had taken place some four years earlier, Tribunal investigators performed a luminol test on the walls and floors of buildings. The test reveals traces of blood, even after blood splatters had been cleaned, by illuminating them. A Tribunal investigator said that the walls in one building where a number of killings took place, called the White House, had so many traces of blood that it “lit up like a Christmas tree.”

In the former Keraterm camp, the same test was performed in one of its buildings where 150-200 men were killed in what became known as the Room Three massacre. The luminol test showed that there had been so much blood on the ground that a foot print was revealed with such clarity that investigators could tell what kind of running shoe it was.

Investigations such as those conducted in Prijedor were performed in dozens of places across Croatia and Bosnia and Herzegovina. The biggest crime scene that the Tribunal would investigate in Bosnia was the massacre of some 8,000 Bosnian Muslim men and boys in the aftermath of Srebrenica’s fall in July 1995. Tribunal investigators conducted their first investigations there in March 1996.

Like in Prijedor, the atmosphere in which Tribunal investigators were operating was tense: the Bosnian Serb Army (VRS) officers, who were under investigation, still held their positions, and the VRS Drina Corps, which was primarily responsible for the massacres, had its headquarters in Vlasenica, the area where Tribunal investigators would be working. As in the Tribunal’s other investigations in Bosnia and Herzegovina, IFOR forces escorted Tribunal investigators in their work, and Tribunal staff stayed in a tent on IFOR’s base in Vlasenica.

Tribunal investigators went to the area to find the detention and execution sites that witnesses had identified in their statements to the Prosecution. At that point the Prosecution still did not know about the VRS’ cover-up operation, in which they exhumed the bodies of the victims and reburied them in secondary graves.

Although eight months had passed since the majority of the executions had taken place, Tribunal investigators still came across evidence of the crimes. They found human remains, including on the side of a farmer’s road, shell casings and personal effects from the victims. At a dump site close to the Grbavci school, a detention site near Orahovac in the north of the municipality, Tribunal investigators found unused cloth ligatures, hand-knit woolen socks, woolen berets typically worn by Muslim men, and canes.

Tribunal investigators also went to the meadow at Sandići village, on the road between Bratunac and Konjević Polje. Bosnian Muslim men had been hiding on a hill overlooking the meadow on 11 July 1995 when VRS forces, who had stolen UN vehicles, called to them promising they would be treated in accordance with the Geneva conventions. In their investigations in March 1996, looking up from the meadow, Tribunal investigators could see the exact path the Bosnian Muslim men took as they descended to surrender: it was marked with the personal belongings they left behind, a kaleidoscope of colours snaking down the hill. In the meadow, where the Bosnian Muslim victims were held before being taken to detention and execution sites, Tribunal investigators found such things as identification cards and cigarette boxes. In the white house across the road, Tribunal investigators saw blood splatters from executions.

For the next several years, between April and October, the Tribunal conducted exhumations in the Srebrenica area. Through extensive witness interviews, including a few survivors and insider witnesses, and with the assistance of American satellite imagery that showed large areas of freshly dug soil on the dates that the executions were occurring, the Tribunal identified a number of locations suspected to hold mass graves.

The Tribunal had an exhumations unit, with its own budget, and hired a range of professionals and other staff to do the grisly work of unearthing evidence of a series of massacres that Tribunal judges would later call genocide. The exhumations team included a diverse range of staff: dog teams which checked areas for mines; archeologists and forensic anthropologists who examined the grave in order to reconstruct the victims’ last minutes of life; pathologists who performed autopsies to identify the cause of death; drivers to transport the bodies from the site to a mortuary where autopsies could be performed; clothes washers, who removed clothing from the decaying bodies and washed them; among others.


When Tribunal prosecutors began work in 1994, they were conscious of being in a very different position to their predecessors in the Nuremberg Tribunal that tried Nazi crimes after World War II. While Nuremberg prosecutors began their investigations with vaults full of documentation that meticulously detailed how the Nazi regime implemented its criminal plan, in their early days Tribunal prosecutors had only open source documents, such as Yugoslav legislation and newspaper articles.

The Tribunal’s Prosecution knew that to find evidence that Slobodan Milošević or his high-level co-perpetrators were involved in crimes on the ground, they would have to get access to documentation. In December 1997, the Tribunal's Prosecution obtained a warrant from a Tribunal judge to search various buildings in Prijedor - including the municipal government offices, police station, and the Serbian Democratic Party Headquarters - and seize documentation.

Again, cooperation with NATO’s forces in Bosnia and Herzegovina was critical to successfully executing the Tribunal’s mission. SFOR accompanied Tribunal investigators when they went to deliver the search warrant to Prijedor’s chief of police. Although Simo Drljača had been replaced, the atmosphere of this meeting with the new chief was nevertheless tense. While the ICTY was delivering the search warrant in Prijedor, SFOR was handing it to Republika Srpska President Biljana Plavšić, who at that time still had not been indicted by the Tribunal. Plavšić called Prijedor's police chief while Tribunal investigators were in the office with him. After this phone call, the Prosecution's mission proceeded without interference.

The Tribunal carried out about half a dozen search and seizure missions in this way. Further missions afterwards were conducted by consent. Over the years, the Tribunal's Prosecution would seize documents from various VRS corps, as well as its Main Staff, from Bosnian Serb police stations, municipal offices, Serbian Democratic Party headquarters and other buidlings.

Valuable documentation for the case against Slobodan Milošević and his co-perpetrators in the Bosnian Serb and Croatian Serb leaderships also came from search and seizure missions to Bosnian Croat, Croatian and Bosnian Muslim buildings. For example, intercepted telephone conversations between members of the Bosnian Serb leadership and Slobodan Milošević came from the Bosnian Muslim army, which had operators recording radio communications throughout the war. Although often interlocutors would speak in code, generally they were fairly sloppy. The Bosnian Muslim army operators, and later Tribunal investigators, were able to identify who was speaking and on what topic. The Tribunal gathered a couple of thousand intercepted conversations, a number of which indicated Slobodan Milošević’s connection to the crimes.

After Slobodan Milošević fell from power in October 2000, Tribunal investigators set their minds to obtaining documentation from Belgrade. The Tribunal Prosecution sent official requests for hundreds of documents relating to investigations in Croatia, Bosnia and Herzegovina and Kosovo to Serbian authorities. The authorities fulfilled a number of requests, but many others became the subject of litigation before the Trial Chamber and court orders.


The Tribunal had interviewed many hundreds of witnesses of crimes committed in Croatia and Bosnia and Herzegovina in its efforts to lay the base of the pyramid for indictments against higher-level leaders. A number had already testified in other cases over the years. Many were prepared to come back to the Tribunal once again to testify against Slobodan Milošević.

Tribunal investigators also contacted and interviewed dozens of witnesses who would later testify about the chain of command leading to Slobodan Milošević. For those among them who were military, police or political officials, the Tribunal had to request the authorities of Serbia and Montenegro to release them from their duty to protect state, military and official secrets. After Slobodan Milošević fell from power, other witnesses with knowledge of Milošević’s role in committing crimes came forward to speak to the Prosecution about what they knew.

Pulling it all together

Investigators, prosecutors, analysts, and case managers pored over the Tribunal’s evidence of crimes committed in Croatia and Bosnia and Herzegovina accumulated over years of investigation. Pulling it all together, they saw that they had constructed the pyramid Richard Goldstone’s strategy envisioned would lead straight to Slobodan Milošević.


The Office of the Prosecutor was the first agency to investigate a sitting head of state as the crimes were happening. Prosecutor Louise Arbour reacted quickly to reports that massive crimes were being committed in Kosovo in March 1999 during a conflict that pitted Yugoslav forces against the Kosovo Liberation Army on the ground and NATO forces that were bombing from the air. Unlike in 1994 when the Tribunal had just opened, in 1999 the Tribunal had the personnel, resources, and experience to be able to respond to these crimes in real time. Prosecutor Arbour sent several investigative teams to both the Former Yugoslav Republic of Macedonia (FYROM) and Albania to take statements from the masses of Kosovo Albanian refugees flooding across Kosovo’s borders.

After NATO forces moved into Kosovo in June 1999, the territory became what many called the largest crime scene to be investigated in history. In the following months, forensic teams from a dozen countries meticulously exhumed thousands of bodies from hundreds of locations where Serb forces killed Kosovo Albanian victims.


The Office of the Prosecutor encountered its first challenges when it began investigating crimes in Kosovo in the autumn of 1998. The Federal Republic of Yugoslavia repeatedly denied Tribunal investigators visas, and prohibited them from travelling to the area. Yugoslav authorities asserted that the Tribunal did not have jurisdiction to investigate in Kosovo as the conflict there was an internal dispute with terrorists.

When Prosecutor Louise Arbour tried to enter Kosovo on 18 January 1999 to investigate reports of the the killing of 45 Kosovo Albanians at Račak, Yugoslav authorities again refused to let her in. Prosecutor Arbour stated that she was determined to investigate this incident and left a team in the region to gather information and evidence. A week later, Yugoslav authorities permitted a forensic team from Finland to conduct autopsies of the Račak victims, together with teams from Yugoslavia and Belarus. The Finnish team’s findings that the victims were unarmed would later be used as evidence in the case against Slobodan Milošević.

Real-time Response

After Serb forces moved into Kosovo en masse on 23 March 1999 and began their campaign to expel the Kosovo Albanian population, the Office of the Prosecutor swiftly dispatched teams of investigators to the region to interview refugees. Hundreds of thousands of Kosovo Albanian refugees spilled out of Kosovo into refugee camps in neighbouring FYROM and Albania.

Tribunal investigators took more than a thousand statements in the period of a couple of months. They were greatly assisted by non-governmental organizations and the Organization for Security and Co-operation in Europe, whose Kosovo Verification Mission had evacuated just before the NATO bombing campaign began and whose personnel were still in the region gathering information from refugees.

Prosecutors would find in the statements a pattern of crimes occurring throughout Kosovo: refugees told Tribunal investigators how Yugoslav army units shelled Kosovo Albanian villages, before Serbian police and paramilitary units moved in to expel villagers, or kill and mistreat them. Many told how Yugoslav and Serbian armed forces seized and destroyed their identity documents, and stole their money and jewelry, before forcing them to cross Kosovo’s borders. Others related how Yugoslav or Serb forces killed their loved ones.

Back in The Hague, teams of analysts scrutinised Yugoslav laws, media reports, documents, intercepted communications, and other sources in order to determine who the Yugoslav military, Serbian police and paramilitary forces committing crimes on the ground answered to. They found that the trail led to Slobodan Milošević and four of the highest level Yugoslav and Serbian political, police and military leaders: President of Serbia Milan Milutinović, Yugoslav Deputy Prime Minister Nikola Šainović, Yugoslav Army Chief of Staff Dragoljub Ojdanić, and Serbian Interior Minister Vlajko Stojiljković.

Through witness statements, analysis of the political, police and military chains of command, and information obtained from governments and non-governmental organizations, Prosecutors found that some 740,000 Kosovo Albanians were deported across Kosovo’s borders or displaced within them, and had evidence at that time that many hundreds were killed (the total killed would later grow to several thousand). On 24 May 1999, with the forces in Kosovo still locked in intense conflict, a Tribunal judge confirmed the indictment against Slobodan Milošević and his four co-accused.

The Largest Modern-day Crime Scene

When the Yugoslav authorities concluded a peace agreement on 12 June 1999, and NATO forces moved in to take control of Kosovo, the ICTY had access to one of the world’s largest crime scenes. The Tribunal’s investigators entered Kosovo one week later, one step behind NATO forces.

The Tribunal had only two forensic investigators on staff, which would clearly not be enough to investigate hundreds of locations where killings allegedly took place. The Prosecution sent letters to every member state of the UN asking them to donate forensic teams. A dozen UN member states and Switzerland responded positively, sending a combined total of some 300 crime scene experts including forensic pathologists, explosives and ballistics experts, and videotape, photographic and mapping specialists.

Before the forensic teams could begin the somber task of recovering evidence from killing sites, the Tribunal first had to identify their locations. Tribunal investigators had information from the witness statements the Prosecution had taken from survivors in Albania and FYROM. Satellite photos also helped lead Tribunal investigators to alleged killing sites. Once in Kosovo, the Tribunal was getting fresh reports of crime scenes on a daily basis from Kosovo’s citizens, NATO forces, non-governmental organisations, UN agencies and journalists.

Tribunal investigators fanned out across Kosovo to conduct a preliminary assessment before sending in a forensic team. If, for example, they saw freshly dug earth, shell casings, or body parts at the location, they knew they were in the right place. Before calling in the forensic team, NATO forces made sure the site was clear of mines or bombs and safe to excavate. NATO also secured sites that Tribunal investigators and forensic teams could not get to immediately.

Like with a murder investigation in a domestic jurisdiction, the forensic teams documented and photographed the crime scenes, collected and preserved evidence such as clothing or spent cartridges, and performed autopsies on the victims in order to reconstruct the last minutes of their lives. The forensic teams found that the main cause of death for most victims was gun shot wounds, while for some it was blunt force trauma. The victims were both male and female, ranging in age from two to 94 years of age.

Some forensic teams were sent to sites where victims had been buried after being killed, others to sites where bodies had been burned or thrown into wells. In many cases, forensic investigations confirmed that killings had taken place. In others, investigations turned up nothing, such as at the Trepča lead and zinc mine in the northern part of Kosovo.

Forensic investigations also turned up evidence of tampering with graves, such as in one location where investigators found freshly turned earth, but no bodies. Later, the Tribunal’s investigators would learn of secret mass graves located in Serbia where the accused and his co-perpetrators had arranged to have the Kosovo Albanian victims’ bodies moved in order to hide evidence from international investigators. Several Serbian Interior Ministry personnel would testify about a refrigerator truck containing bodies of Kosovo Albanians that was found in the Danube river in eastern Serbia (see the Prosecution’s Kosovo case), and about exhumations of some 800 bodies that had been moved. Such evidence was very significant for the Prosecution because it provided clear evidence that the perpetrators knew they were breaking the law.

The victims’ family members were often involved in the process of investigating crime scenes. They granted permission to the Tribunal to exhume the remains of their family members, were present during exhumations, identified them, and even helped to rebury them. For example, a 90 year-old man gave the Tribunal permission to exhume the remains of his 86 year-old brother. Afterward, he helped to rebury him, and took a rake to smooth the grave over.

From the end of June to 1 October 1999, when exhumations stopped because of weather conditions, forensic teams working with the Tribunal found 2,108 bodies in 195 grave sites throughout Kosovo. The following year, from April to October 2000, forensic teams investigated another 325 sites and exhumed 1,577 bodies and body parts in another 258 cases. The evidence collected from these exhumations corroborated witness accounts that showed a pattern of killings committed by Yugoslav and Serb forces.

In addition to demonstrating that these forces committed crimes in Kosovo, Tribunal investigators also had to prove that they were connected to Slobodan Milošević and his high-level co-perpetrators. Publicly available Yugoslav legislation and media reports provided critical evidence of the chain of command.

When NATO forces moved into Kosovo, another valuable source of documentation became available to Tribunal investigators. The Tribunal found hundreds of documents that helped the Prosecution make its case that the crimes were committed by forces subordinate to Slobodan Milošević and his co-accused. However, Tribunal investigators also found evidence that a great many documents had been destroyed.

Soon after Slobodan Milošević was ousted from power in late 2000, the Office of the Prosecutor was able to reopen its office in Belgrade, which had been closed during the conflict in Kosovo. The Prosecution now had a platform from which it could further develop its investigations. Tribunal investigators monitored the Serbian authorities’ exhumation of the mass graves of Kosovo Albanian victims in Batajnica, a Belgrade suburb, and Petrovo Selo, in eastern Serbia. Tribunal investigators also used the Belgrade office to work on the investigation of the chain of command leading to Milošević for crimes committed in Croatia and Bosnia and Herzegovina, as well as Kosovo.

An Unprecedented International Effort

The investigation against Slobodan Milošević was unprecedented in its scope, nature and in the international expertise it applied to the task. Over the years, dozens of prosecutors, investigators, analysts, case managers, language and support staff from a number of different countries worked on the investigation of Slobodan Milošević for crimes committed in Croatia, Bosnia and Herzegovina and Kosovo. Whether they were listening to witnesses’ wrenching accounts of what they suffered, unearthing victims’ bodies from mass graves, poring over documentation, painstakingly organizing the voluminous evidence, or presenting it before the judges, the Prosecution staff worked to bring evidence of Slobodan Milošević’s crimes to the public. Their efforts produced 932 prosecution exhibits and 295 witness testimonies, the vast majority of which are publicly available.

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