Two former Serbian intelligence chiefs go back on trial before UN judges on Tuesday, accused of running death squads which terrorised Bosnia and Croatia in the 1990s Balkans wars.
Jovica Stanisic, 66, and Franko Simatovic, 67, were initially acquitted in 2013 of four charges of crimes against humanity and one charge of war crimes by the International Criminal Tribunal for the former Yugoslavia (ICTY).
But their acquittal, which triggered a storm of protest, was overturned two years later after the prosecution appealed.
The two men were ordered to return to the tribunal in The Hague to face a retrial on the same charges.
Stanisic, the former head of Serbia's old state security service and a key figure in the regime of Slobodan Milosevic, and his deputy Simatovic now stand accused once again of organising, financing and supplying paramilitary groups.
These groups cut a swathe of terror and destruction across Croatia and Bosnia during the conflicts that erupted amid the collapse of Yugoslavia.
They included an elite unit dubbed the "Red Berets" and the feared paramilitary outfit run by Zeljko "Arkan" Raznatovic, called "Arkan's Tigers".
- 100,000 people killed -
The death squads attacked towns and murdered Croats, Muslims and other non-Serbs to force them out of large areas, seeking to establish a Serb-run state, prosecutors alleged, as they called for life sentences for both men in the original trial which opened in 2008.
UN prosecutors maintain that Stanisic and Simatovic were part of a joint criminal enterprise that included the late Serbian president Milosevic and Bosnian Serb leader Radovan Karadzic.
An estimated 100,000 people died in the Bosnian conflict, which saw some of the worst atrocities in Europe since World War II, and during which 2.2 million people were forced from their homes.
The indictment alleges the joint criminal enterprise began "no later than April 1991 and continued until at least 31 December 1995" with the aim of "the forcible and permanent removal of the majority of non-Serbs from large areas in Croatia and Bosnia and Herzegovina".
But the ICTY's trial judges said in May 2013 that although the Serbian units carried out the killings, Stanisic and Simatovic could not be held criminally responsible as they did not give the units specific orders to commit the crimes.
The trial judges also said there was not enough evidence linking the men to a joint criminal enterprise.
- Back behind bars -
In a rare turnabout however, that judgement was quashed on appeal by the prosecution in December 2015, when the appeals court found that the trial judges had "erred" on several points of law.
Court officials said it was only the second time in the court's 23-year history that an acquittal had been overturned on appeal.
With the ICTY due to shut its doors at the end of 2017, the re-trial is now being heard by a different UN tribunal wrapping up outstanding cases.
Stanisic and Simatovic, who were both granted temporary release pending the new trial, are now back behind bars having returned to the UN detention centre in The Hague on May 30.
They are among the last top Balkans officials still being held in The Hague.
Milosevic died in 2006 while in the ICTY's custody. Karadzic was last year sentenced to 40 years in jail on charges of genocide, war crimes and crimes against humanity -- notably for his role in the 1995 Srebrenica massacre in which almost 8,000 Muslim men and boys were slaughtered.
He has appealed, but no date has been set for a new hearing.
A verdict is also keenly awaited at the ICTY in the case of former Bosnian Serb army chief Ratko Mladic. Dubbed "the Butcher of Bosnia," he has denied 11 charges, including two of genocide.
The acquittal of Stanisic and Simatovic capped a series of such acquittals in 2012-13 of high-ranking Croatian and Serbian generals and officials, which triggered criticism of the tribunal.
A former ICTY judge later alleged the court's president, judge Theodor Meron, had pressured other judges to acquit the accused, suggesting possible pressure from the United States -- accusations that have never been proven.
© 2017 AFP