The suspect -- who was not identified -- was detained in the gambling hub of
Macau, 40 kilometres (25 miles) west of Hong Kong, and sent back by ferry to
Hong Kong, where he was arrested, police said.
Superintendent Steve Li said Macau police and the Hong Kong Organised Crime and
Triad Bureau were involved in the case.
"At the time of the arrest we were able to recover two mobile phones which had
been stolen from two of the victims," Li said on local radio RTHK.
"At the moment the arrested person is being detained for further enquiries. We
believe that at some point later we will be issuing criminal proceedings."
Li said it appeared that robbery was the motive behind the murders of the four
women.
"We do not want to guess, but based on the information so far we gathered, and
also the ransacking and the looting of properties, we believe there's one
possibility of robbery," he said.
Hong Kong is one of the world's safest major cities, and murders and other
violent crimes are rare. The four murders brought the total for the year to 14,
according to the South China Morning Post.
About 30 representatives of sex workers' groups staged a sit-in outside police
headquarters demanding to meet Commissioner Tang King-shing over the murders,
accusing police of not taking their concerns seriously, RTHK said.
One of the protest organisers told the radio station they were still worried
that there could be more attacks despite the arrest of a suspect.
Organisations representing sex workers have urged the government to amend the
law to allow two women to work together for safety.
Under Hong Kong law, prostitution is legal if carried out by one woman
operating alone in a single location, such as her apartment -- the so-called
"one-woman brothel". Soliciting for sex is illegal.
Many of Hong Kong's sex workers are women from mainland China who enter the
territory on tourist visas in the hope of making some money.
