Amsterdam's most notorious criminal Willem Holleeder has lost his appeal against a nine-year prison sentence. The Amsterdam court said on Friday it is convinced that Mr Holleeder blackmailed three businessmen, Willem Endstra, Kees Houtman and Rolf Friedländer.

The court upheld the decision by a lower court to accept as evidence recordings made of conversations between Mr Holleeder and property dealer Willem Endstra, who was later killed, as was Kees Houtman. "But these recordings should be used cautiously," presiding judge Mr Chorus said.

Mr Holleeder's lawyers claim that Mr Endstra lied in those conversations in order to protect another prominent criminal who had engaged Mr Endstra's help for money laundering activities. They demanded Mr Holleeder's acquittal, but that was rejected by the court. The lawyers say their client will appeal to the court of cassation.

Willem Holleeder will continue to serve a prison sentence for blackmail, which extends until January 2012. The original 12 years were reduced to nine as the court took into account Mr Holleeder's poor health. He suffers from a heart condition.

In 2008, when he was already in detention, Mr Holleeder was arrested on a further suspicion, of being involved in the murder of Yugoslav drugs dealer Serge Miranovic in 2006.