BELGRADE, Serbia (AP) — A Serbian appeals court has stopped a landmark trial of eight former Bosnian Serb police officers charged with taking part in the 1995 Srebrenica massacre.

The court in Belgrade said Thursday it has accepted defense complains that the indictment against the eight is invalid because it was filed when Serbia did not appoint the chief war crimes prosecutor. The ruling meant that the whole proceeding will have to start over from scratch.

The trial that started in December was the first time that a Serbian court has dealt with the killings by Bosnian Serb troops of around 8,000 Muslim men and boys in the Bosnian town of Srebrenica. It was Europe's worst single atrocity since World War II.

The trial was seen as a test of Serbia's pledge to deal with its wartime past.