Mr Slobodan Milosevic has denied he ordered a "clean-up" to hide the execution of Albanians in disputed Kosovo by moving their corpses to mass graves near Belgrade.
During cross-examination at the Hague Tribunal into war crimes, he disputed the testimony of Serb police captain Mr Dragan Karleusa, who headed a task force to investigate reports of a freezer truck containing 86 bodies that was believed to have come from Kosovo.
Prosecutors say executions were part of a Serbian ethnic cleansing campaign in Kosovo of majority Albanians overseen by Mr Milosevic, the former Yugoslav president, who is charged with genocide and crimes against humanity in Kosovo, Bosnia and Croatia during the break-up of Yugoslavia in the 1990s.
During his investigation, Mr Karleusa was told about a meeting in March 1999, in which Milosevic was said to have ordered a "clean up" in an attempt to cover up crimes in Kosovo.
Mr Karleusa learned what is alleged to have happened from a statement of a participant, former state security chief Mr Rade Markovic, who is also in The Hague waiting to testify.
But Mr Milosevic said he did not believe Mr Markovic could have said something like that "because it is not true." Mr Milosevic said Serb authorities publicised the discovery of buried corpses near Belgrade to prepare the public for his transfer to the UN war crimes court.
Mr Karleusa denied there was any political motive.