Hong Kong victims of an investment scam have been urged to come forward after suspected members of an international gang of con artists were arrested in Cambodia. Twenty foreigners face prosecution in Cambodia on suspicion of operating a share trading racket and setting up an unlicensed international telephone calling system, police said. Commercial Crime Bureau investigators yesterday appealed for Hong Kong victims to contact them after military police cracked the gang operating the hi-tech investment scam out of a Phnom Penh office on Tuesday. It is understood the alleged mastermind of the operation, believed to be a Briton, eluded capture and is on the run in Thailand. It was not known how much money the alleged fraudsters may have conned from unwary investors. However, during police interrogation, the gang members revealed they had been targeting financial backers in Hong Kong, Australia and many countries in Europe. Officials at the Post and Telecommunications Ministry believe the unnamed foreigners encouraged investors to buy stocks and bonds in companies that were suspect or did not exist. The gang of 14 Britons, two Americans, an Australian, a New Zealander, a Filipino and a Thai used a computer and international phone system that bypassed official phone companies. They will now be asked to pay more than US$27,000 in charges for the calls, authorities said. Khut Sopheang, a city prosecutor, said the suspects had been released but could not leave the country because their passports had been withheld by authorities and would not be returned until the charges were paid. He said he would not take legal action against the foreigners 'who appeared to have been employed by some masterminds'. Chem Sangva, deputy director of the Inspection Department at Cambodia's Ministry of Telecommunications, said the suspects 'were very sophisticated and skilled people' who 'stayed online 24 hours a day to trade shares, to sell stocks'. 'The total bill is now US$27,678, and we are going to make them pay the money,' he said. Mr Chem Sangva said it took authorities nearly three weeks to pinpoint the exact location in Cambodia from which the calls were made to Hong Kong, Australia and Europe. 'They used to operate in Laos, but after problems there they moved to Thailand,' said Mr Chem Sangva. 'However, Thailand knows about them, so they moved to Cambodia.' The operations are known as boiler rooms because of the high-pressure environment in which the traders work. Two years ago Thailand uncovered a huge boiler room which was mainly targeting Australians. The scams gained worldwide publicity in 2000 with the release of the Hollywood blockbuster Boiler Room, starring Giovanni Ribisi, Vin Diesel and Ben Affleck. Set in New York, the film charted the rise and fall of an unlicensed brokerage, showing the aggressive tactics used by traders to con unsuspecting investors. Police in Southeast Asia have periodically closed companies in which western sales staff use high-pressure cold calls to sell bogus shares.