Cheung partnered with Yip Kai-foon in a series of armed robberies. On , he raided Kai Tak Airport where he hauled a HK$30 million consignment of Rolex wristwatches. On , Cheung returned to Kai Tak, where he robbed a security van, netting HK$167 million, Cheung was arrested in September 1991 and jailed for 18 years for the security van heist. However, he was acquitted and released after appeal in June 1995 when the judge ruled there was no case against Cheung as the evidence was filled with too many inconsistencies and the security guard who initially identified him recanted his testimony. His associate Yip, however, was sentenced to 41 years in jail.