The case of an undocumented 12-year-old boy who spent nine years in hiding yesterday became the focal point for protests from radical groups complaining about local resources being used to help non-Hongkongers. The protesters earned condemnation for surrounding the offices of the lawmaker who was helping the boy, Siu Yau-wai, and targeting a school he visited after his case came to light. Their actions proved too much for one pupil of the school, who burst into tears upon seeing protest posters featuring the boy plastered on the school doors. The protesters said lawmaker Chan Yuen-han's high-profile handling of the case, including revealing Yau-wai's identity, was not in his best interests. They also expressed concern that allowing an illegal migrant to stay would set a dangerous precedent. "Chan Yuen-han, go to hell, Siu Yau-wai, return to the mainland," the crowd of about 40 people shouted at Chan's Wong Tai Sin office and the nearby Confucian Tai Shing Primary School. Yau-wai's case had gripped the city since Thursday, when his grandmother Chow Siu-shuen, 67, disclosed she had brought him to Hong Kong while he was just three. The boy had since been largely confined to their flat for fear of being caught, she said. Chow was arrested for aiding and abetting a person in breaching conditions of stay, while Yau-wai received temporary papers pending investigation. Yesterday, Chan, a veteran Beijing loyalist, was branded a "Hong Kong traitor" in posters that the protesters - most of whom were from the groups Civic Passion and Localism Power - plastered on her office. She was not present at the time. The groups then moved to the school, whose principal had earlier voiced interest in offering the boy a place should the authorities allow it. They linked Yau-wai's case to wider issues of cross-border ties and immigration policy. "If you let him stay, next thing we know, mainland parents will be abandoning their children in Hong Kong for a few years so they can get identification [papers]," Jon Ho of Localism Power said. Fellow protester Adam Chan Ho-sze added: "The child is to be sympathised with, but the way [Chan] is using his case - it does not seem to be in the boy's best interests." Chan said the pair's decision to go to the authorities meant they were prepared for punishment. She said she had called a media conference on Thursday because she hoped the complex case could be dealt with openly. Lau Kar-wah, a lawyer helping them out, said the pair had been moved from their Kwun Tong public flat to a safe place. "After what happened [yesterday] it's obvious that this is necessary." Education sector lawmaker Ip Kin-yuen said the protest had scared pupils. He said whether Yau-wai could stay in the city had nothing to do with the school. Another group, Hong Kong Indigenous, will march from Sogo in Causeway Bay to Immigration Department offices in Wan Chai at 2.30pm tomorrow.