Two schoolgirls and another woman appeared in the District Court yesterday charged with trafficking in dangerous drugs, a result of a police operation in which an undercover officer posed as a Form Four pupil and infiltrated a Tuen Mun school. Tang Tsz-yan, 18, Leung Tsz-kwan, 16, and Apple Lai Pui-sze, 32, pleaded guilty to six, two and five counts of trafficking in dangerous drugs respectively. They were caught in a four-month undercover operation that has to date led to 69 people aged between 13 and 35 being charged. Prosecutor Winston Chan Lap-yan described how a police officer, who was in his 20s, was deployed as an undercover agent and enrolled as a student in a secondary school in November last year. The officer met Tang and Leung at the school and Tang later introduced him to Lai. The court heard that the three had sold Ice and ketamine to the officer on several occasions for between HK$400 and HK$2,500 in shopping centres, car parks or stairwells. In mitigation, Tang's lawyer said the girl had first taken drugs when she was 13 after being introduced to substances by Lai, her godmother. Deputy District Judge Bina Chainrai adjourned sentencing to August 30, pending background reports on the three. All three were remanded in custody.