Police, lawmakers and social workers yesterday warned youth drug abuse was spreading, and a legislator voiced shock at the failure of police to act on drug-taking at one of the city's top schools. Senior police officers questioned whether it was appropriate to continue giving schools the discretion as to whether to call in police over drug incidents. They spoke as a spate of ketamine abuse by youngsters continued, with three teenagers found to have taken it at a beach. Rosaryhill School, on Stubbs Road, said four girls were found to be high on the drug at lunchtime on Tuesday. While the school reported the situation to police, no action was taken. The Catholic school's vice-principal Kitty Ho said the girls had confessed to taking the drug in a changing room. She said Rosaryhill had contacted the Wan Chai police school liaison officer that day. Since no drugs were found on the girls and they did not become ill, the officer thought the school could handle the case, she said. No formal report was made to police. Education sector lawmaker Cheung Man-kwong said he was outraged that the police took no action. 'It is hard to believe that the police school liaison officer asked the school to handle the case themselves,' he said. 'They must take action to find the dealers and trace the drug sources if they are to prevent the students taking drugs again.' Mr Cheung said he would file a complaint to Police Commissioner Tang King-shing about the handling of the case. A police spokesman said the school liaison officer could not take follow-up action on the day 'as no concrete details were provided'. Officers would go to the school tomorrow and hold an anti-drugs seminar there on Wednesday. Rosaryhill is one of the city's most exclusive schools. Former pupils include Bernard Chan, until recently an executive councillor, singer Kelly Chen Wai-lam and Twins singer Charlene Choi Cheuk-yin. Mr Cheung said youth drug abuse had spread to privileged schools and society must address the problem. After the school went public yesterday, two 15-year-old schoolgirls and another teenager were found dazed on a beach in Tuen Mun at about 4pm. They were suspected to have taken illegal drugs. The three were arrested with a woman, 21, who was charged with possessing drugs. On Thursday police arrested three pupils of Pak Kau College, Tin Shui Wai, on suspicion they had taken ketamine after they fell ill in a nearby park. Police caught a schoolmate who allegedly sold the ketamine to the three. A veteran police officer said 'grey areas' in the handling of drug cases should be done away with. 'Unlike smoking a cigarette, taking psychotropic drugs will kill abusers and damage their brains,' he said. 'We should let the courts decide what rehabilitation programme is suitable for drug abusers.' Another senior officer, with more than 20 years' experience, said enforcement should be used if education and social work failed to control the problem. Deputy Secretary for Education Betty Ip Tsang Chui-hing said schools might not intend to hide drug problems, and should be allowed flexibility as to whether or not to report cases to the police. Lawmaker James To Kun-sun agreed schools, not police, should be allowed to handle minor cases to help students' rehabilitation. Police figures show 17 students were found taking drugs at schools in the first three months of this year, compared with 24 in the whole of last year and 37 in 2007. The leader of a team of Caritas outreach social workers, Forest Chan Chi-sing, said the number of students taking drugs and involved in drug trafficking was growing.