London ? Preliminary toxicology tests on former Yugoslav leader Slobodan Milosevic found no evidence of poison or the presence of other drugs in quantities sufficient to kill him.

Milosevic had a fatal heart attack a week ago in his prison cell in The Hague, ending his four-year trial on charges of war crimes and genocide.

His family says he was poisoned. Others suspect suicide. Friday’s findings, disclosed in a letter from The Hague district public prosecutor, are likely to deepen the controversy.

Milosevic suffered from high blood pressure and a heart condition. In blood samples taken in January, doctors were startled to discover traces of an unprescribed drug that would have had calamitous consequences for someone with high blood pressure. That finding has fueled speculation that Milosevic may have been trying to manipulate his health to persuade the war crimes tribunal to allow him to seek treatment in Russia.

The drug, rifampicin, normally is used to treat tuberculosis