The media cited the prosecutor's office as saying that the crime was committed by members of an armed group called "Cipat" in the zone which was then under the command of Ramush Haradinaj who is the current prime minister of Kosovo.
According to the indictment, on 12 June 1999 Lakaj committed an attack on a Roma wedding in Kosovo's Djakovica manicipality, killed four people, and raped and abused guests at the wedding.
Lekaj trial will be the first process against an ethnic Albanian before the Special War Crimes Court in Belgrade, spokesman for the prosecutor's office Bruno Vekaric told Radion B92.
Lekaj was arrested in Montenegro in late August, on a warrant issued by the District Court in Kosovo's Pec.