BELGRADE, Serbia, July 23 (UPI) -- Captured alleged war criminal Radovan Karadzic posed as a healer, transforming his appearance to evade detection, Serbian officials said.

Karadzic, the Bosnian Serb leader accused of the deaths of 20,000 people, had lived under an assumed identity, practicing alternative medicine at a clinic in Belgrade and sporting a flowing beard and long, white hair, The Independent reported Wednesday.

Serbian security forces snatched Karadzic Monday from a bus.

Meanwhile, pressure mounted on Serbia to turn over to authorities Ratko Mladic, also accused of war crimes, The Independent said. Mladic was believed to have been living under the protection of the Serbian military intelligence community until recently.

The capture of Karadzic is a key condition for Serbia to join the European Union, the British newspaper said. The other conditions are the capture and surrender to the U.N. war crimes tribunal of Mladic and Croatian Serb Goran Hadzic.

Karadzic and Mladic were indicted in 1995 by the International War Crimes Tribunal for the former Yugoslavia after the massacre of more than 7,500 Muslim men and boys in Srebrenica. Hadzic is wanted in the execution of 250 prisoners after the siege of Vukovar, Croatia, in 1991.