The mysterious disappearance of Carlos Castaño, the storied paramilitary chieftain who helped found Colombia’s right-wing death squads in the 1980s, has thrown the country’s already rocky peace process into turmoil. President Alvaro Uribe had been in negotiations with Mr. Castaño, trying to demobilize some 20,000 paramilitary combatants. Now analysts and paramilitary leaders both say that the government and the United Self-Defense Forces of Colombia (AUC), the group originally organized by Castaño, are likely to take a harder line in negotiations that were already threatening to fail, possibly leading to renewed violence.Full Story