SARAJEVO: Human rights investigators have received a green light to begin excavating sites of suspected mass graves as early as Friday, according to United Nations officials in Sarajevo. "It's a good sign that the United Nations is serious about looking for evidence," says TIME's Massimo Calabresi. "But this is less significant than if they were to go somewhere controlled by the Serbs, who, by all accounts except their own, have committed most of the atrocities during the war." Manfred Novak, a U.N. investigator, will supervise digging at three sites near the central Bosnian town of Jajce, now controlled by Bosnian Croats, because unseasonably warm weather and floods have unearthed dozens of bodies in the area. Adds TIME's Alexandra Stiglmayer: "The International War Crimes tribunal still plans to begin the real investigations of mass grave sites, like those around Serb-held Brcko and Srebenica, in the spring. Since the town fell relatively late in the Serb's offensive, everyone knew that they were ethnically cleansing. Most of the Croats and Muslims fled before the Serbs arrived. It was a pretty organized retreat. So it could be that the bodies they are finding are either soldiers or old people who couldn't flee or people who lived in the mountains and didn't know that the town was falling."