Dutch businessman Guus van Kouwenhoven - convicted of smuggling weapons from the mainland via Hong Kong to Liberia - will be spending the next eight years behind bars thanks to vital evidence unearthed by local police. Van Kouwenhoven last week managed to shake off war crimes charges but could not escape being convicted of breaking the UN arms embargo in Liberia - due, in part, to the testimonies of up to 10 Hong Kong witnesses. The announcement of the verdict came days before an Amnesty International report on arms smuggling which is expected to name China as one of the world's biggest arms exporters. The report, due to be released today, will show mainland-sourced weapons have helped sustain brutal conflicts, criminal violence and other grave human rights violations in countries such as Sudan, Nepal, Myanmar and South Africa. According to Desiree Leppens, spokeswoman for the prosecutor's office in Rotterdam, five to 10 witnesses were located by Dutch authorities in Hong Kong in late April after Hong Kong police handed over a file detailing van Kouwenhoven's local business connections. The captain and crew of the MV Antarctic Mariner - a Panamanian-registered ship owned by Hong Kong-registered Global Star (Asia) - confirmed weapons were smuggled on board. In addition documents, including a logbook, showed the ship's route from the mainland to the Port of Buchanan in Liberia. Investigations by the Sunday Morning Post revealed that the Antarctic Mariner had been 'detained' for unspecified reasons by Hong Kong authorities for five days in July 2003 and had last docked in the city on November 16 last year. The 22,009-tonne bulk carrier now goes by a new name - Raffles - but its whereabouts is not known. Ms Leppens added that local police also managed to track down a director and another former employee of Global Star (Asia) - the Hong Kong importer for van Kouwenhoven's Oriental Timber Company (OTC) - in Singapore. Director Anthony Ho Kui-hing, a Hong Kong resident, refused to testify at the trial, but the employee agreed to assist Dutch authorities. Global Star (Asia) group is no longer listed, but OTC is still operating locally. Van Kouwenhoven's links to Hong Kong were first exposed by human rights and environmental group Global Witness in 2003. In a damning report, the group identified a number of local companies which off-loaded Chinese-made AK-47s, machine guns and rocket-propelled grenade launchers in Africa. It accused OTC - Liberia's biggest logging firm - of shipping Liberian timber to the mainland to either exchange for weapons or to sell and pay for weapons. OTC was allegedly awarded a concession to exploit 1.6 million hectares of forest, encompassing 42 per cent of all trees in Liberia, in exchange for weapons. According to a statement by Greenpeace International, van Kouwenhoven's verdict will have 'far reaching implications for the international timber trade'. 'This case illustrates that the international timber trade is still unable to regulate itself,' said Greenpeace International Africa forest campaigner Stephan van Praet. 'The lack of legislation at the international level on imports of illegal or conflict timber contributed to this horrible example of destructive exploitation of a natural resource, fuelling civil war and related crimes against humanity.'