A cross-border smuggling syndicate that used a 300-metre fishing line to ferry gadgets from Hong Kong to Shenzhen has been smashed in a joint operation by customs officers from both sides of the border. Its alleged mastermind, a Hong Kong man who was released from jail only last month after being convicted for identical crimes three years ago, was arrested with five mainlanders in Shenzhen on Wednesday, a customs official said yesterday. Law enforcers confiscated 100 Apple iPad2s and iPhone4s valued at more than HK$300,000 at the pick-up point in Shenzhen. Equipment, including a giant home-made conveyance wheel and a fishing line, was also seized. Hong Kong customs officers are looking for two other smugglers who fled in a seven-seater car from the uploading site in Sha Tau Kok, Hong Kong. A Hong Kong customs official said the investigation indicated that the syndicate started operating about two weeks ago, days after its mastermind was released from jail in Hong Kong. 'Investigations showed that smugglers operated in the small hours of each morning in an attempt to avoid detection,' the officer said. 'A black nylon bag containing smuggled goods was tied to the black fishing line and pulled across the border. It is very hard to discover at night.' The Hong Kong site was in the waterfront area near the Sha Tau Kok River off Lin Ma Hang Road, where a one-metre metal pole was planted in the ground and fitted with a pulley. The pick-up point was on the other side of the river on the 21st-floor bridge connecting two high-rise residential blocks, where the 1.5-metre-diameter wheel was installed. The fishing line was attached to the wheel and lowered from the bridge before being shot across the river and connected to the pulley on the Hong Kong side. 'Only one bag containing either two iPads or several iPhones was uploaded to the fishing line in Hong Kong each time because the line was not strong enough to carry more,' the officer said. 'Smugglers in Shenzhen spun the handle of the giant wheel manually to pull the bag to the mainland side. They made 40 to 50 passes each night.' Customs officers from both sides began investigating the syndicate after receiving a tip-off last week. In the early hours of Wednesday, mainland officers arrested five men and one woman and seized the haul at the bridge and a nearby apartment in Shenzhen. There were no arrests and no goods were found in Hong Kong.