I think he was just 'assisting'. He is the 'assistant' ME. BUT, it was thought that by using a CHINESE man (a trainee) instead of the actual person who did the examination (probably the technicians), the Jury would be impressed by his 'kung fu' and ignore any inconsistencies and chalk it up to 'miscommunication'.
He signed it — not his technicians. He is the Medical Examiner — associate or other. He is to be held accountable.