Police are hunting for another 100 suspects who played an “active role” hurling bricks, setting fires and causing mayhem in the Mong Kok riot a fortnight ago, the Post has learnt. Sources in the force said as most of them had concealed their faces with masks, goggles, hats and clothing, police had deployed a special team to pore over surveillance camera footage to figure out their identities. The Post understands the elite organised crime and triad bureau is also investigating whether the rioters received financial support from secret backers. Of the 100 suspects, a source with knowledge of the investigation said: “Officers could only identify them when their masks were removed and they were captured by surveillance cameras. That is why we have to seize hundreds of CCTV recordings from different channels to check.” Describing them as “active” participants of the clashes that left nearly 130 people injured, the source added: “They were on the site, hurling bricks, setting fires, assaulting police, damaging public properties and involved in the clashes with officers.” Another source said police would trace others who played a less active role later, and the force might release photographs of the masked rioters to seek the public’s help in identifying them. So far, 74 people – 65 males and nine females – have been arrested. The youngest are two 14-year-old girls out on bail. More than 40 were charged with rioting. Some of those arrested are said to be from the localist group Hong Kong Indigenous and radical activist group Civic Passion. The latest swoop was on Sunday when officers broke into a public housing flat in Tin Shui Wai and arrested Ray Wong Toi-yeung, 22, convenor of Hong Kong Indigenous, and a 28-year-old man. Wong – who disappeared after a February 11 posting that it was “better to die with honour than survive in disgrace” – was arrested for inciting others to take part in the riot. Inside the flat, officers seized bottles of chemicals that could be used to make explosives. It is understood these included ammonium nitrates, silicon dioxide and polyethylene glycol. Bomb disposal officers removed the chemicals for examination. The organised crime and triad bureau is investigating the source of the chemicals. Police also seized HK$530,000 in denominations of HK$500 and HK$1,000 along with about 100 tablets of what is believed to be Viagra, an extendable baton, a Guy Fawkes mask, an electromagnetic gun and circuit boards. It is understood that officers were told the money was from donations collected by one of the localist groups. Last night a hooded and handcuffed Wong was escorted by police to his home in Choi Ming Court, Tseung Kwan O, for a search. He was driven away an hour later for further questioning. Wong, a freelance interior designer, co-founded Hong Kong Indigenous in January last year . The group operates on the principle of using violence to fight “oppression” and has rejected the more peaceful approach adopted by the Occupy movement in 2014. The group claimed police had arrested more than 20 of its members since the Mong Kok riot, but sources said six known members of the group including Wong had been nabbed.