LONDON -- For years, former Bosnian Serb General Ratko Mladic lived openly in Belgrade at 119 Vlagoja Parovica Street. He treated with utter contempt his indictment by the International Criminal Tribunal for former Yugoslavia for directing the slaughter of 7,045 Muslim men and boys at Srebrenica in July, 1995 -- but last week, Mladic suddenly went underground.

The net is starting to tighten. In January, Biljana Plavsic, former president of the Bosnian Serb Republic, surrendered to the Hague tribunal to face trial for genocide and war crimes. (Plavsic once suggested that Muslims were "genetically deformed," and she was photographed in 1992 stepping over the body of a murdered Muslim to kiss Arkan, most brutal of the Serbian paramilitary leaders.)

That was followed on Saturday by the Serbian government's arrest of Rade Markovic, former head of the Serbian secret police, on suspicion of multiple murder. If he talks, the trail of evidence will quickly lead not only to Mladic but to the men in charge of the whole Bosnian genocide, former Bosnian Serb leader Radovan Karadzic and former Yugoslav President Slobodan Milosevic. And it's not just in the Balkans that progress is being made.