Summer job-seekers have been warned to beware racketeers, following two cases of blackmail last month. Two victims, both aged 19, were lured to Macau by advertisements promising jobs as tourist guides. Syndicate members detained the pair in Macau and demanded ransoms of $30,000 and $88,000. Police arrested four syndicate members aged between 19 and 36. 'Police are determined to crack down on this kind of unlawful activity and further arrests are expected,' Western District's Assistant District Commander (Crime) Donald Logan said. Job-seekers should: discuss potential jobs with their families; be alert to suspicious details like job interviews in public places; and remember the addresses of locations to which they are taken.