“Everyone remembers the harrowing footage of the Srebrenica massacre shot by Zoran Petrovic, the only cameraman to capture the events on film. But this week’s fascinating documentary shows that the very worst of his pictures never reached our TV screens. Key scenes from Petrovic’s rushes were ‘lost’ or blacked over, presumably to prevent reprisals. We unearth the lost images, and the completed jigsaw is even more heinous than the already blood-spattered picture. Amazingly, Petrovic has never been interviewed by the War Crimes Tribunal about what he saw. For the first time, his incriminating material is available for scrutiny.