A police officer went undercover as a prisoner to help bust a triad gang that sent in members posing as visitors to deliver messages and goods to inmates at Lai Chi Kok Reception Centre.
Officers believe messages to inmates awaiting trial may have concerned their upcoming court cases, with one senior police officer saying the activities could pose a risk to the judicial system.
Four men and five women, including the gang's mastermind, were arrested in a series of raids yesterday. Officers are hunting at least six more people in connection with the case, described as the first of its type in the city.
But police said the content of the messages the gang arranged to have passed on remains a mystery. Officers will interview 150 inmates to try to find answers.
The reception centre in Cheung Sha Wan accommodates male prisoners awaiting trail, as well as men detained under the Immigration Ordinance.
Superintendent Lau Tat-keung, assistant district commander for Sham Shui Po, said the implications of the messages could be severe. He said: "This is a potential danger to our whole, entire judicial system, by telling an inmate what to do."
The gang, which ran a company in Cheung Sha Wan, had been operating for a year, police said. Lau said the gang's recruits made 353 paid visits to 152 inmates, with the shortest lasting just 30 seconds.
"The price [charged by the gang to pass on a message or hand over items] is about HK$130 to HK$150 per visit," he said.
Police said no banned items such as drugs entered the centre through the visits, with the main items delivered being cigarettes and daily necessities.
Sham Shui Po district crime squad began investigating after gang members handed out fliers to visitors and put up a banner to promote the delivery services outside the centre last August.
According to the Prisons Ordinance, only relatives and friends of an inmate are allowed to visit.
The department has a list of declared visitors for each inmate.
But a police source said officers at the reception centre had to handle many remand inmates each day and may have been unable able to put together the lists quickly enough. He said the gang made use of this grey area to pose as friends of the inmates.
The arrested members are being investigated for conspiracy to defraud, which carries a maximum sentence of 14 years in jail.
The reception centre's chief officer for administration, Sun Wai-yeung, said monitoring of visitors had been stepped up.