A triad-linked vice racket that ran about 30 one-woman brothels housing mainland prostitutes in Tai Po was smashed by police in an undercover operation that ended in a series of raids.

Officers have arrested the ringleader – a 58-year-old woman – and three suspected Sun Yee On triad members along with 10 mainland women.

Investigations indicated the syndicate brought mainland prostitutes into Hong Kong and arranged for them to live and work in the brothels in three tenement buildings in the district, according to police.

“The syndicate provided cleaning services in the rooms and arranged food for prostitutes, but pocketed half of the money the women charged their clients,” a police source said.

“It also hired triad members as security who acted as lookouts.”

The syndicate installed surveillance cameras outside each brothel and the entrance of the buildings so that the mastermind and members of the triad security team could monitor its business through computers and mobile phones, according to police.

“The prostitutes charged clients HK$380 for sex, but they had to pay between HK$180 and HK$200 to the syndicate. Investigations showed one woman could serve more than 10 clients a day,” the source said.

“We believe the syndicate could pocket as much as HK$1 million a month from the illegal prostitution business,” the source said. Police believe the vice ring had been in operation for several months.

Officers began investigating the gang in December and undercover policemen were deployed to collect intelligence and gather evidence.

After a two-month probe, anti-triad officers from Tai Po police district and immigration officers raided tens of locations including brothels in Wai Yan Street and Tsing Yuen Street in Tai Po on Thursday.

Police arrested the alleged ringleader at her home in Wai Yan Street on Thursday night. Three alleged members of her security team, believed to be Sun Yee On triad members, were picked up in the streets.

Officers arrested 10 mainland prostitutes in the brothels. All were two-way permit holders.

Yesterday, the 14 suspects were being held for questioning and none of them had been charged.

Also on Thursday, police and immigration officers arrested four Hongkongers – three women and one man – and 14 women visitors from the mainland in a crackdown on a Wo Shing Wo triad gang which demanded protection fees from one-woman brothels in Sheung Shui.

Police are searching for a number of triad members in connection with the case. Investigation by the Tai Po anti-triad squad is continuing.