A gang of suspected thieves from the mainland was arrested after pearls worth HK$250,000 were stolen on the first day of a Hong Kong international jewellery show on Lantau on Tuesday. Five mainlanders – one man and four women – were picked up at the AsiaWorld-Expo venue of the Hong Kong Jewellery and Gem Fair hours after its opening ceremony, police said. On Tuesday night, the five suspects were being held for questioning and had not been charged. Officers from the New Territories South regional crime unit were investigating. A police source said it appeared more female jewellery thieves in recent years had been sent from the mainland to target Hong Kong’s jewellery show. “Their tactics are simple,” he said. “One of them distracts staff at a booth as others steal valuables.” The source added some thieves were believed to have been trained to use a fake diamond to swap for a real gem. Cash, jewellery and watches worth HK$480,000 stolen from luxury house in Sha Tin The seven-day jewellery show is being held at two venues: AsiaWorld-Expo at Hong Kong International Airport and the Convention and Exhibition Centre in Wan Chai. The AsiaWorld-Expo segment, running from Tuesday to Saturday, showcases raw materials including diamonds, loose gemstones and pearls as well as equipment and packaging. Their tactics are simple. One of them distracts staff at a booth as others steal valuables police source on jewellery thieves The Wan Chai event, which runs from Thursday to Monday, highlights fine finished products. More than 3,600 exhibitors from 55 countries and regions are taking part in the events. About 58,000 buyers from around the world were expected to attend. It is understood plainclothes officers have been deployed at the fair as well as private security guards and surveillance cameras. Hong Kong’s jewellery shows are no strangers to crime. A year ago, a suspected thief from the mainland was arrested in possession of a fake diamond that police believed she intended to swap for a real gem before a show. In June last year, diamonds and other jewels worth more than HK$6.9 million were stolen in 17 thefts over a four-day period during a show at the Convention and Exhibition Centre.