Crucial information supplied by SAR investigators helped mainland police snare the alleged Panyu killers. Sources say key meetings in Hong Kong and Macau enabled members of a special taskforce set up by Guangdong Public Security Bureau to pinpoint a dispute over smuggling as the clearest motive for the mass killing. Initially, detectives in Macau, aware of the casino-related activities of the main target of the attack, known 14K triad and Hong Kong resident Ng Chun-fai, thought the mass execution on June 7 was linked to arms smuggling. But meetings later in June between the mainland taskforce, which included officers from the elite squad which cracked the case of executed gangster 'Big Spender' Cheung Tze-keung, and detectives from the SAR's Organised Crime and Triad Bureau (OCTB), Criminal Intelligence Bureau and Narcotics Bureau, homed in on drugs as the motive. Yesterday, Hong Kong detectives played down their role. OCTB Senior Superintendent Sin Kam-wah said: 'We're flattered that they gave us a mention.' Ng is known to have been involved in the smuggling of mainland robbers and weapons into the SAR in the late 1980s and early 1990s. He is also thought to have had connections to the Macau underworld.