About a kilo of suspected ketamine was discovered in two salt packets in a garment-declared air parcel from Pakistan on October 11, and four kilos of suspected methamphetamine in two toy-declared air parcels from Thailand on November 1.
As the parcels were meant for the same address, officers suspected a connection and a 43-year-old woman and a 37-year-old man were arrested in Tsuen Wan on Friday.
In another development, officers inspected an air consignment from South Africa on November 1, where about 6.5 kilos of suspected methamphetamine was found inside ink rollers.
Officers arrested a 34-year-old man in Tsim Sha Tsui in connection with the case on Friday.