Glass and medicine mixed with ketamine, court told Drug dealers mixed glass and a medicine that cures bladder conditions with ketamine to reduce the cost, the District Court was told yesterday as two students and a man appeared on drug related offences. They were among 69 people arrested in an undercover operation in which a male police officer posed as a Form 4 pupil and infiltrated a Tuen Mun School last year. Shu Ka-wo, 21, Cheng Yi, 17, and Leung Wai-kit, 16, each pleaded guilty to two counts of trafficking in dangerous drugs for selling ketamine to the police officer between December and January. Cheng and Leung each pleaded guilty to another two counts of trafficking in purported dangerous drugs. Deputy District Judge Bina Chainrai adjourned sentencing to September 7. Bystander, 70, charged over clash with hawker patrol A 70-year-old man was charged with one count of common assault and one count of obstructing a public officer in the execution of her duty after he was accused of pushing a female hygiene officer on to the floor in Ngau Tau Kok yesterday. The incident happened after Food and Environmental Hygiene Department officers caught an unlicensed hawker, 74, selling nail scissors in Yee On Street. The man, a passer-by, was accused of trying to stop officers.