'The Empress' Deposed.(Biljana Plavsic)

In the end, Biljana Plavsic must have known that she had nowhere to run. Three days before Christmas, the U.S. ambassador to Bosnia, Thomas Miller, paid a discreet visit to the 70-year-old former biology professor at her apartment in the capital, Banja Luka. For months Plavsic had been hearing rumors that The Hague tribunal had secretly indicted her for crimes committed as a key leader of the Bosnian Serb government during the bloody ethnic cleansing of Bosnia in 1992. The rumor was true, Miller told her, and she faced a brutally simple choice: flee into hiding like her former crony Radovan Karadzic or surrender and hope for lenient treatment. Shaken, Plavsic asked for permission to travel to Belgrade to meet her beloved brother for the Orthodox Christmas on Jan. 7, promising to return to Bosnia immediately afterward. Later, she called her attorney, Krstan Simic, and told him the news. "I asked her, 'Do you intend to escape?' " recalls Simic. "And she replied, 'No, I am a man, not a mouse'."

Last week the trap sprang shut. In a packed courtroom in The Hague, the first woman to be indicted by the tribunal pleaded not guilty to charges of genocide and crimes against humanity. Then she was locked in a second-floor cell at The Hague's detention center. Plavsic's surrender marked a dramatic victory for chief prosecutor Carla Del Ponte, who has been struggling to erase the perception that the court has been slow in bringing Bosnian war criminals to justice. Plavsic's detention will almost certainly increase pressure on the main architects of the conflict: fugitives Karadzic and military commander Ratko Mladic. And, if Plavsic cooperates, her testimony could prove vital in building a case against Slobodan Milosevic, who still has not been indicted for his role in the war in Bosnia, which many consider his biggest crime.

Plavsic was an unlikely candidate for infamy. The daughter of prominent academics in the northern Bosnian town of Tuzla, she studied viral biology in Zagreb and earned her doctorate in the United States on a Fulbright scholarship. After decades of teaching abroad and a brief marriage to a Serb lawyer, she became the dean of sciences at Sarajevo University, then a symbol of multiethnic coexistence. But as the contagion of Serb nationalism spread through the former Yugoslavia, Plavsic became a true believer. Some say her deep devotion to the Serb Orthodox Church may have stoked her passions. In 1990 she cofounded the hard-line Serbian Democratic Party (SDS) along with Karadzic. She served as a member of the three-person presidency of the breakaway Serb republic and was present at all key meetings of the Bosnian-Serb command as troops and paramilitary units swept through Bosnia in 1992. Neatly coifed with color-coordinated purses and dresses, she presented a civilized contrast to the male hard-liners in the wartime government. Says Branko Todorovic, president of the Helsinki Committee for Human Rights in the eastern Bosnian town of Bijeljina: "She was a scholar who seemed out of place among a group of ruthless men."

In fact, Plavsic may have been the most fanatical of them all. At the outset of the Bosnian war in April 1992, she traveled to Bijeljina, after it had been brutally cleansed of its Muslim population. There she planted a famous televised kiss on the cheek of Arkan, the notorious paramilitary commander who had led the assault, and she praised him as "a Serb hero." In 1993 Plavsic declared that ...