A TEENAGER who was found trafficking in almost 400 grams of heroin mixture was yesterday sentenced at the High Court to five years' jail. Sentencing Wong King-yin, 19, Deputy Judge Daniell said the most important mitigation was the guilty plea, which was an indication of some degree of remorse. Prosecuting counsel Frank Veltro told the court that Wong was intercepted by police outside a Tsz Wan Shan restaurant in the evening of October 19, 1992. When searched, a total of 386 grams of a mixture containing 147 grams of salts of esters of morphine was found in the bag Wong was carrying. His counsel, Wong Po-wing, said Wong had to close his hawking business, which he ran with some friends, after they had a dispute. He became unemployed, and as a result agreed to act as a heroin courier at $150 per delivery for a man called Ah Keung. At the time of his arrest, Wong had worked as a courier for only a week and had made about 10 deliveries, said counsel. He urged the court to take into account that Wong had given useful information to the police.