A Serbian court has found 12 men guilty of the 2003 assassination of the pro-Western Prime Minister Zoran Djindjic in Belgrade.
Zoran Djindjic wanted to extradite war crimes suspects
All the defendants, who include members of the secret police and alleged mafia kingpins, had denied the charges.
Two former policemen - Milorad "Legija" Ulemek, 39 and Zvezdan Jovanovic, 41 - received 40-year jail terms.
The prosecution argued Djindjic was killed to block his reforms, including the extradition of war crimes suspects.
The trial was the first at Belgrade's Special Court for Organised Crime.
The other 10 men received between eight and 35 years for their part in the assassination. Five of them are still on the run and were tried in absentia.
"It was not an ordinary murder, it was a political murder with the aim of destabilising the state," Judge Nata Mesarevic said.
Ulemek, an ex-French Foreign Legionnaire, and Jovanovic were said to be the ringleaders of the plot. They had been members of the Red Berets police unit.
Some of the other 10 found guilty had also served as paramilitaries in the Bosnian, Croatian and Kosovan conflicts.
"It was all prepared by Ulemek. Jovanovic fired the shots," Judge Mesarevic said.
According to the Reuters news agency, Jovanovic wrote a statement saying: "I liquidated Zoran Djindjic personally. I was not interested in the money. I did it to prevent extradition of our people to The Hague."
One gang member, Dejan "Bugsy" Milenkovic, who had been wanted for previous attempts on Mr Djindjic's life, was arrested by police in Greece in 2005.
The charges against him were withdrawn under a plea bargain, reports said.
Dubbed Serbia's "Trial of the Century", the case was beset by problems.
One protected witness and another eyewitness were murdered, while one judge resigned and another received death threats.
Outside the court on Wednesday the relatives of those jailed were booed and whistled by protesters, the BBC's Nick Hawton reports.
The former prime minister was getting out of his official car outside government buildings in Belgrade when he was fatally shot by the sniper on 12 March 2003.
He had come to power following the toppling of Slobodan Milosevic's government in 2000 and his murder sent fresh shockwaves through the country.
A state of emergency was declared and more than 10,000 people were arrested in a massive police operation.
Half a million people attended Mr Djindjic's funeral in a huge outpouring of national grief.
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