NATO troops entered Kosovo two weeks later to oversee a withdrawal by Serbian forces and set up a temporary UN administration. Alongside western troops came war crimes investigators who launched a massive effort to locate bodies of ethnic Albanians killed during the war.

Forensic teams from around the globe, including the FBI, eventually exhumed some 4,000 bodies, though the estimated death toll remains higher. Investigators first task was to quickly put meat on the bare-bones indictment against Milosevic, which was drawn up largely from the accounts of Albanian deportees interviewed in neighboring countries during the air war.

"Our greatest fear was that Milosevic would simply turn himself in and we would be stuck with an indictment we couldn't prove," admitted one ICTY investigator in July 1999.

In its amended form, the ICTY indictment for Kosovo alleges that Milosevic and four top Serbian officials participated in a "joint criminal enterprise," whose aim was the expulsion of a substantial portion of Kosovo's ethnic Albanians to secure continued Serbian control over the province.

The indictment describes "widespread and systematic" human rights violations, including deportations, destruction of homes and property, murder and rape. In all, the indictment alleges some 800,000 ethnic Albanians were expelled from the province by troops under Milosevic's command.

Milosevic faces four counts of crimes against humanity and a total of more than 60 counts in all three indictments. In Bosnia, Milosevic is charged with genocide, the most serious of all war crimes.

The original Kosovo indictment was based on Milosevic's formal authority as commander of Serbian and Yugoslav forces in wartime. To the delight of ICTY prosecutors, Milosevic has boasted to the court of his role as commander-in-chief during the Kosovo war.

But legal observers say that in order to convict Milosevic, prosecutors must prove that the Serbian leader had active, or "de facto" control over his troops in Kosovo.

RELATED LINK Milosevic's Chain of Command (PDF File) Researchers for New-York based Human Rights Watch have detailed Slobodan Milosevic's army and police command structure in Kosovo as part of an extensive investigation into the Kosovo war. Under Yugoslav law, Milosevic was commander-in-chief of all police and army units in wartime, including paramilitaries. Elite secret police units led by Franko Simatovic and Milorad Ulemek Lukovic coordinated most attacks in western Kosovo during the air war, according to Serbian police and military sources.

"If he was commander in title only that is not sufficient for a conviction," says Michael Scharf.

"Prosecutors are going to have a show a very clear chain of authority, and that Milosevic had effective control over the acts committed in Kosovo. That he could stop them if he wanted and that he could punish individual perpetrators if he desired," he says.

Investigators say Milosevic did not leave a paper trail connecting him to specific war crimes or even to commanders and units who carried out deportations and murder in Kosovo.

Scharf compares Milosevic's disdain for written orders to Richard Nixon. "Nixon was famous for telling his subordinates, 'you know what I want to do, read my thoughts and do it.' He didn't specify in particular what he wanted. Milosevic had that same kind of leadership style. He would give general guidance. He would say the Kosovo Liberation Army (the ethnic Albanian guerrilla group) is a problem, deal with it. And perhaps his subordinates would read into it what they thought he meant," says Scharf.

The ICTY indictments maintain that Milosevic created a secret state together with a cabal of Serbian officials throughout the former Yugoslavia in order to exert Belgrade's control over much of the country. ICTY chief prosecutor Carla del Ponte argues that Milosevic's "joint criminal enterprise" is the key link between events in Croatia, Bosnia and Kosovo over a ten-year period.

But the challenge remains for prosecutors to provide convincing evidence that Milosevic actively controlled the conspiracy, and thus is directly connected to killings and deportations in the field.

Because of Milosevic's formal authority over Serbian forces, the Kosovo prosecution was widely seen as an "open-and-shut" case for Carla del Ponte. But as recently as last summer ICTY field investigators were in a frantic search for direct evidence against Milosevic. According to sources close to the tribunal, investigators had little documentation and no direct testimony against Milosevic.