Testimony The exact testimony of each different witness was crucial to the prosecution's case. Mr Leung says, "We took the view that when the assistant engineer who had only just graduated started work on the Yuen Chau Kok site, the piling works were already close to completion. With only a few weeks of work experience, he had merely executed his superior's instructions without knowing much about what was going on. We hence proposed to the Department of Justice that he be exempted from prosecution and take the stand as a tainted witness." Similarly, the site foreman and the assistant engineer who had been transferred away from the Yuen Chau Kok site also became tainted witnesses, and testified in the case against the "Hui Hon Trio". Details of testimony against the Hui Hon Trio Witnesses Testimony Site foreman and assistant engineer - Two ex-directors of Hui Hon, ignoring the caving in of pile shafts, instructed staff to continue the construction works. - The site agent instructed staff to forge reports of the length of temporary casings and the quantities of concrete. Assistant engineer - Two ex-directors of Hui Hon instructed staff to use Super Mud without approval from HD and to conceal excess concrete left over by ordering staff to use it for road paving. Site foreman and newly employed assistant engineer - Two ex-directors of Hui Hon and the site agent respectively instructed them to arrange for workers to take a number of core samples from piles that met the required standard and use them to replace poor quality cores. - The site agent instructed the site foreman to forge records of core samples.