THE HAGUE, Netherlands — A Dutch toxicologist today said he found traces of an unprescribed drug in Slobodan Milosevic's blood earlier this year, after the former Yugoslav leader's blood pressure failed to respond to medication given at the U.N. detention center.

Donald Uges said he found traces of rifampicin, a drug that "makes the liver extremely active," so that other medications would break down very quickly, possibly losing their effectiveness.

Milosevic, 64, had a history of heart problems and high blood pressure, and took medications to treat those conditions.

A legal aide to Milosevic, Zdenko Tomanovic, meanwhile, said today that the late Serb leader would be buried in Belgrade, in a funeral that could provoke tumultuous scenes in the capital that he ruled for 13 years before he was extradited to stand trial for war crimes.

Milosevic was found lifeless on his prison bed Saturday morning, just hours after writing an accusatory letter alleging that a "heavy drug" had been found in his bloodstream.

The allegations in what amounted to Milosevic's deathbed letter put the tribunal and U.N. prosecutors on the defensive about whether they had given Milosevic the medical treatment he needed and whether they had conducted the trial properly and effectively.

Tomanovic, said the ex-president feared he was being poisoned, claiming that traces of an antibiotic he had never taken had been found in his blood.