Slobodan Milosevic's lawyer has produced a letter in which the former Yugoslav president claimed he was being poisoned.
The letter was purportedly written on Friday, one day before his body was discovered in prison in the Netherlands.
Hours after the lawyer's claim, a Dutch news report said traces of a drug used to treat leprosy and tuberculosis were found in a blood sample taken in recent months from Milosevic.
The report cited an unidentified "adviser" to the UN war crimes tribunal.
The UN announced that an autopsy had found Milosevic died of a cardiac arrest. But it said more tests were need to determine what triggered it.
But in Serbia, several newspapers published stories that supported rumours of poisoning and allegations that the one-time "Butcher of the Balkans" had been murdered while in UN custody.
Doctors had found traces of the drug when they were searching for an answer to why Milosevic's medication for high blood pressure was not working, the report on Dutch state broadcaster NOS said.
Milosevic was examined last January, according to his legal aide, Zdenko Tomanovic.
The report did not identify the drug found in Milosevic's blood "in a test done in recent months", but said it could have had a "neutralising effect" on his other medications, reports the Age.
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