Witness in Serb leader's assassination found dead
His charred body with wrists handcuffed behind its back was found beside a highway to Belgrade, the state news agency Tanjug quoted police as saying.
He was identified by his family as Zoran "Vuk" Vukojevic. Police looking for the killers blocked the main bus station and searched cars crossing Belgrade's two main bridges over the Sava river, snarling Saturday evening traffic.
Djindjic was shot dead by a sniper on March 12, 2003 while entering his Belgrade office. Crime bosses linked to the secret police of the era of late Serbian President Slobodan Milosevic are charged with his murder.
Vukojevic was a key member of the mafia-style 'Zemun Gang' alleged to be behind the assassination. As an insider he had given valuable testimony.
Thirteen people are indicted for Djindjic's murder, six of whom are still at large. The trial started at the end of 2003 but has been stalled by technicalities and the killing of another witness.
It was not immediately clear how Vukojevic's death would affect the trial, which includes two other protected witnesses.
At the time of his death, Djindjic was moving against organised crime gangs that thrived in the 1990s.
The suspected mastermind, former special police commander Milorad Lukovic, denies all charges as does the alleged sniper.