A HONG KONG-born waiter and three Vietnamese boat people face a possible death sentence next month when they stand trial in a tiny West African state accused of one of the most unlikely coup attempts in the trouble-torn region. Kelvin Law Shu-kee and the three other Asians, all naturalised Britons, are alleged to be mercenaries who were plotting to overthrow Sierra Leone's military dictatorship when they were arrested on October 14, 1993. Law, 32, Ly Bui Vinh, 24, Ly Bui Hai, 32, and Ly Nhat Mui, 50, have been held for more than a year in a crowded cell in the country's main jail in the capital, Freetown, after being detained in the Mammy Yoko hotel. A fifth man, local Chinese restaurateur Robert Charm, was arrested on December 30, 1993, but was later released. According to prosecutors, the men had been sent to Sierra Leone by the former deputy head of state, Captain Solomon Musa, to depose the country's ruler, Valentine Strasser. However, the main evidence against Law and his three companions is a tape recording implicating the men - which has not been produced yet - and a road map found in their hotel and marked with what the prosecution claim are strategic sites for an attack. The men, three of whom live and work in the Birmingham area of Britain, were not carrying any weapons when arrested. Nonetheless, they were committed for High Court trial in May after a magistrate found there was sufficient evidence to warrant a case. At the time, their lawyer, Terence Terry, told the magistrate that it was absurd to believe that four restaurant workers, all of whom were born in Asia, could be involved in a coup attempt just because of a road map. Diplomatic sources in Freetown have described the saga surrounding their arrest and the coup allegations as 'ridiculous' and a 'farce'. They believe the men were set up as part of a campaign to discredit Captain Musa, who was sacked in July last year and went into exile in Britain, where he is now studying law. At one stage, the four, who are visited regularly by British Commission staff, went on hunger strike to protest against the charges. David Harris, British Consul in Freetown, said they are being held in the Pademba Road Prison and the High Court hearing was due to start shortly. The group, who were travelling on British passports, claim they were on holiday in Freetown when they were arrested the day before the alleged uprising was due to take place. Captain Strasser came to power in 1992 when a group of young army officers, including Captain Musa, overthrew the then ruler, Joseph Momoh.