Handcuff case spurs lawmakers to demand police chief explain co-operation with Public Security Bureau Lawmakers will press Police Commissioner Dick Lee Ming-kwai to reveal how many times mainland Public Security Bureau officers have come to Hong Kong to investigate crimes in co-operation with local officers. The police chief, who is due to appear before the Legislative Council security panel's monthly meeting tomorrow, faces questions after the police force's repeated failure to provide the information in response to requests over the past week. Democrat and panel chairman James To Kun-sun said he would demand that the number of official cases of co-operation with mainland law enforcement agencies be disclosed. This comes a week after the Sunday Morning Post revealed that two mainland officers arrested for loitering and possessing a pair of handcuffs on Mount Davis Road last year will not be prosecuted. Further details have emerged about why the Department of Justice chose to abandon prosecution of the two officers. A government source said investigators could find no evidence the PSB officers intended to use the handcuffs unlawfully. A police spokeswoman said mainland law enforcement agencies who wanted to carry out investigations in Hong Kong must seek approval in writing from senior force management. The request must include an outline of the background of the case and what assistance was required from the Hong Kong police. 'All investigative actions must be carried out by Hong Kong authorities, and at no point are mainland security officers allowed to take any enforcement measures,' the spokeswoman said. Despite repeated requests over the past week for details of the numbers of such visits, up to last night the force was unable to say how many times the mechanism had been used by the Public Security Bureau since 1997. 'We need to actually go through the individual files by hand to collate the information. It's going to take a long time,' the spokeswoman said. Mr To said he did not understand why police had withheld such information. 'Since the mainland authorities must write to the Hong Kong Police's Liaison Bureau to ask for assistance, all the police have to do is to go to the bureau office and look up the number of requests,' he said. A government source said the Department of Justice decided in September not to prosecute the two Guangdong officers because investigators were unable to find evidence the pair intended to use the handcuffs unlawfully. 'The burden of proof is on the prosecution,' the source said. Under Hong Kong law, anyone found guilty of possessing an offensive weapon with intent can be fined up to $5,000 and jailed for up to two years. A similar offence, possessing an offensive weapon in a public place, can land offenders over 25 in jail for three years. The source said the additional charge local police were investigating - that of loitering causing concern, with a maximum sentence of two years' jail - could not be established because the pair's presence was reported by a casual passer-by in a car and not the supposed subject of their alleged surveillance. Earlier in the week, Secretary for Security Ambrose Lee Siu-kwong told a Legislative Council meeting that the mainland law enforcers were caught with a pair of handcuffs because one of them had 'carelessly' forgotten to leave them at the office before coming to Hong Kong. The Hong Kong authorities have accepted an explanation by Guangdong officials that the officers were on a 'sightseeing' trip.