A SHAMPOO boy grabbed a girl and threatened her at knifepoint before robbing her and her friends of cash and jewellery as they walked along a beach, a court heard yesterday. Lo Kai-wah, 16, was sent to a training centre after pleading guilty to robbery before Judge Hawkes. Senior Crown counsel Miss Evena Chan told the District Court that on February 25 Lo grabbed Ms Lau Hiu-san, 18, by the neck from behind as she walked with friends on Repulse Bay beach. He threatened her at knifepoint and ordered her five companions to hand over their money and gold jewellery. The court heard that Lo told them to leave after they had given him more than $1,000 and a gold ring. Seconds later, Lo accosted Mr Tse Man-choi and Ms Leung Wai-yee on the beach, grabbing Ms Leung by the neck from behind, the court was told. He robbed them of a total of $1,770, two gold rings and a Rolex watch. Lo tried to escape, but was arrested by two patrolling police officers. He had been seen throwing away a knife and the stolen property by the officers, the court heard. Defence counsel Mr Ricky Ng said his client had committed the offence under the influence of soft drugs. The court heard that Lo had two previous convictions.