Constable Tsui Po-ko had been spying on prominent political figures - including Lau Wong-fat, Philip Wong Yu-hong and Raymond Wu Wai-yung - and had recorded details of their movements in his diary before he died in the Tsim Sha Tsui shoot-out, an investigator told the Coroner's Court yesterday. 'Tsui Po-ko was very much interested in political figures and organisations,' Senior Inspector Yau Nai-keung told the inquest. 'There were notes concerning 20 to 30 local political figures and they are all usually labelled as Beijing loyalists. Most attention had been paid to three of them. 'We have conducted interviews with these persons and the information in those notes was verified to be accurate,' the inspector told the joint inquest into the deaths of Tsui and three others, including shoot-out victim Tsang Kwok-hang. 'The longer the duration of the surveillance, the greater the threat to the target if there was any vicious motive behind it,' said Senior Inspector Yau, who investigated diaries for 2005 and 2006, together with 54 pages of documents found in Tsui's locker at Tung Chung police station. Senior Inspector Yau hesitated when he was asked by coroner's officer Arthur Luk Yee-shun SC for the names of the targets, saying that he was instructed not to disclose the names. But at the request of Coroner Michael Chan Pik-kiu, he revealed Mr Lau, Mr Wong and Dr Wu, who died last year, were the main targets of the surveillance, which was carried out on Tsui's days off. He also noted Tsui had probably collected a lot of their personal information by searching the internet and keeping news clips during the surveillance between March 2005 and January last year. The 54 pages of documents included printouts of websites profiling the three politicians. Handwritten notes were also found of personal particulars such as their cars, drivers, telephone numbers and addresses. Senior Inspector Yau said names of legislators such as Chan Yuen-han, Ma Lik and Chan Kam-lam also appeared in the diary but a lot less information was recorded about them. The notes and diaries contained their car plate numbers and records of their attendance at places and events such as Legco and offices. The opening hours of Dr Wu's clinic had been recorded, as well as times when Mr Lau attended Legco meetings. '[Tsui] also made notes on whether these people had hired a driver, and sometimes he even recorded the movements of their cars,' he said. The name and residential address of previous chief executive Tung Chee-hwa were found in the 2006 diary under the column '2006 important event', but police had not investigated this entry. Under the same column, there were notes concerning an alleged observation on the Gun Club Hill Barracks of the People's Liberation Army by Tsui. 'It was believed that Tsui had made observation of the changing of shift in the barracks in April 2005. He noted the mode and logistics of the handing over of machine guns among the four guards,' Senior Inspector Yau said, adding that a residential address of an army commander was in the 2006 diary. The body of Tsui was found in an underpass in Austin Road, Tsim Sha Tsui, early on March 16 last year after the shoot-out, in which police believe he gunned down Tsang and Constable Sin Ka-keung, who survived. The inquest is also investigating the deaths of constable Leung Shing-yan at a housing estate on March 14, 2001, and security guard Zafar Iqbal Khan during a bank robbery on December 5, 2001.