Up to 200 gangsters from two major triads across the city were mobilised to infiltrate the camps of supporters and detractors of the Occupy protests during chaos in Mong Kok more than a week ago, police said. Their exact motive was still under investigation, but police planned to launch operations targeting those triads soon. "They were well organised and came with a purpose," Superintendent Dan Ng Wai-hon, of the Organised Crime and Triad Bureau, said yesterday. "Police have been keeping a close watch on some senior triad members. Some have gone into hiding already." The mayhem that broke out on October 3 and 4 led to the arrests of 47 people, of whom at least eight were found to have triad backgrounds, though all were low-ranking members. Since October 5, the force had assigned about 300 plain-clothes officers from the Criminal Investigation Department to Mong Kok to prevent triads from creating more trouble, Ng said. Their numbers were six times more than the usual 40 to 50 plain-clothes officers deployed in the area, he said. Investigators were also checking whether the triads were trying to end the protests, which had harmed their businesses, or had been paid to add fuel to the fire. It is understood there are no signs pointing to any involvement by rural strongmen or their affiliated triads. The protest in Mong Kok began on September 28, hours after Occupy Central organisers launched their democracy sit-in. It started at the junction of Argyle Street and Nathan Road, and has since spread to nearby streets. Multiple sources blamed various factions of the Wo Shing Wo triad for the Mong Kok disorder. It was aided by the Sun Yee On triad, which sent its members to provoke trouble and lead the crowd to challenge police officers trying to maintain order. Of the October 3 chaos, one police source said: "They split into two groups, but most of them posed as supporters of Occupy students. This group wore yellow ribbons and mixed with protesters, while the other donned blue ribbons and mingled with Occupy opponents. "They stirred up trouble at different locations around the junction. As officers tried to stop the clashes, the gang, standing behind the students, hurled stones, hard objects and plastic water bottles. Some even punched our officers." Wo Shing Wo also sent its "operation squad", comprising 20 South Asians, to Mong Kok on those two days, according to an anti-triad officer. Merging into the crowd, the group waited to incite Occupy protesters to charge at a police cordon on Portland Street in an apparent move to stop officers escorting a suspect into a police van at about 2am on October 4. They hurled bricks at the police, who later found two bags of bricks at the scene. It is understood that Wo Shing Wo's businesses have been hit hardest by the protests in Mong Kok - the stronghold for many of its mahjong parlours, upstairs nightclubs and minibus routes. "The commission a triad gains from a large mahjong parlour at night can reach as much as HK$80,000 to HK$100,000 an hour," another anti-triad officer said. Ng described as "ridiculous" accusations that police had colluded with triads, saying the low police presence in the area on those two days was because of a lack of intelligence information. "There were triads in Admiralty too, but even though we know they are triad members, we cannot arrest them if they do nothing more than sing songs for democracy," he said.