The first witness is set to give evidence at the resumed war crimes trial of former Bosnian Serb military chief Ratko Mladic, about Serb forces violently purging his village in 1992.
Prosecutors said the first witness will be Elvedin Pasic, who was just 14 when Serbs overran his village and imprisoned men, women and children in a makeshift detention camp at a nearby school.
Mladic's trial started in The Hague, Netherlands, on May 16, but was almost immediately halted because prosecutors admitted that an apparent clerical error meant they failed to disclose to defence lawyers thousands of pages of evidence.
Mladic faces 11 charges of genocide, war crimes and crimes against humanity. He denies wrongdoing.
If convicted, he faces a maximum sentence of life imprisonment.