KISANGANI, Zaire: It's difficult for 100,000 people to vanish without a trace, but that's what's happened in eastern Zaire. Relief workers say several refugee camps, each of which held tens of thousands of Rwandan refugees only a few days ago, are entirely deserted -- and no one knows what happened to the people. Rebel forces had sealed the area off Monday, allegedly to protect the Rwandan Hutu refugees against rampaging villagers. When U.N. aide workers were allowed to return to the camps days later, no one was left. Refugees have abandoned the camps before, usually when rebels approached and chased them away. But always they have left behind hundreds or thousands of people too weak to walk. U.N. officials now fear that large numbers of the refugees may have been killed. Relief workers flying over the nearby area have spotted only scattered small groups. U.N. High Commissioner for Refugees Sadako Ogato has appealed to rebel leader Laurent Kabila for assistance in the search, but so far the answer to the disappearance remains hidden in the dense forests of eastern Zaire.