Icac investigator wendy yip lai - lin and members of the investigation team then faced the daunting task of sifting through evidence involving multiple defendants . this required the development of considerable technical expertise in canadian immigration procedures and legislation 廉政公署调查员叶丽莲与其他调查人员,面对由多名被告人的证供中,用心过滤有用证据的差事从不气馁,其中更牵涉必须引用大量加拿大移民法例和程序上的专门知识。