Taiwan-Hong Kong police story: inside the secret joint operation to rescue the wealthy businessman kidnapped by the world's most notorious triad

The release of wealthy Hong Kong businessman Wong Yuk-kwan from a 38-day kidnap ordeal in Taiwan was the result of a hush-hush police operation that pushed the boundaries of politically sensitive cross-strait diplomacy.

Sources with a knowledge of the delicate moves required to secure the release of the 68-year-old chef-turned chairman of Hong Kong-listed Pearl Oriental Oil Company told the that cooperation between Hong Kong's organised crime and triad bureau and Taiwan's police was instrumental in securing his safe release.

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Wong was blindfolded, chained and under the guard of two kidnappers when Taiwanese police stormed a secluded house overnight on Tuesday. Detectives from both sides believe one of Taiwan's biggest organised crime groups - the United Bamboo gang - was hired by persons unknown to snatch the businessman, who is embroiled in a fraud trial in Hong Kong.

Fifteen people - all Taiwanese and including members of the United Bamboo triad gang - were picked up in a series of raids across Taiwan.

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"All of them were only carrying out orders," Tsai I-hsueh, a detective from New Taipei City's Xindian district in charge of the investigation, told the . "We are still investigating the motive and the whereabouts of any mastermind."