He said some of the account holders were domestic helpers who were paid thousands of Hong Kong dollars a month to rent or sell their bank accounts to the syndicate.

Chief Inspector Wu Hoi-ling of the Kowloon East technology and financial crime unit said intelligence revealed the racket began operating in February last year, focusing primarily on Hong Kong and Southeast Asian countries.

She said the syndicate set up an overseas gambling website offering games such as baccarat, slot machines, fishing games, lotteries and horse racing.

“To draw in more punters, the gambling website also introduced new gambling options related to major sports events, such as the recently concluded Paris Olympics in August and the new season of English Premier League football matches,” Wu said.

To evade police detection, the syndicate hosted the gambling platform servers abroad and used the Tseung Kwan O flat as a front to set up its operations centre, she said.

According to the force, the group used social media to promote the gambling website and hunt for punters.

Senior Inspector Wong Yuet-chun of the same unit said the syndicate offered multiple accounts under the faster payment system or cryptocurrency e-wallets for clients to top up game points before gambling on the website.

She said the racket also recruited intermediaries to help find stooge accounts to collect illegal bets and make payouts.

“To circumvent scrutiny from the police and banks, its core members withdrew bets in cash and bought various cryptocurrencies to launder the illicit funds before transferring them to its mastermind,” Wong said.

The senior inspector said the group rented a significant number of stooge accounts from intermediaries on a monthly basis. Rents ranged from HK$4,000 to HK$7,000 per account.

Police arrested five men and seven women in a series of raids across the city between Saturday and Tuesday.

One of the locations raided during the four-day arrest operation, code-named “Skyocean”, was the Tseung Kwan O flat used by the syndicate as its operations centre.

Officers seized about HK$170,000, three computers, 386 bank cards for stooge accounts, 211 SIM cards and 218 mobile phones at the premises, as well as luxury watches, jewellery pieces and handbags believed to be used for money-laundering purposes.

Chief inspector Wu said the syndicate’s betting records and profits were stored on the three computers.

“Within just five months from April to August 2024, the syndicate collected a total of HK$250 million in bets, an average of HK$50 million per month,” Wu said. “The group’s net profit during this period was around HK$16 million.”

Police said the 12 suspects, aged 20 to 56, included core members of the syndicate and several holders of the stooge accounts.

The source said the arrested account holders included Indonesian nationals working as domestic helpers.

The 12 suspects were detained on suspicion of bookmaking and money laundering. They have been released on bail pending further investigation.

Police said further arrests were not ruled out as the investigation was still ongoing.