The Customs & Excise Department has uncovered a money laundering case involving $3 billion - the largest ever amount among similar cases handled by the department - and arrested six people.

Five of the arrestees are members of a family suspected of having used personal bank accounts to launder money from unknown sources since 2018. The other arrestee is the licensee of a local money changer.

Briefing the media on the operation this morning, Customs Syndicate Crimes Investigation Bureau Head Mark Woo said customs officers raided four residential flats and a licensed money changer on September 10.

“The family opened more than 100 personal bank accounts to process 6,000 transactions since 2018. The majority of the transactions were from unknown sources or shell companies. We are very suspicious that the assets held by these family members do not commensurate with their profiles and their financial background.

“Two of the family members are unemployed while the others are declared as a technician, a manager and customer service officer and their monthly salaries ranged from $15,000 to $30,000. However, they had $15 million (in) bank deposits and held two land properties valued at $7 million to $8 million respectively.

“We suspect that this family had hidden income, which may be the process of assisting in money laundering.”

Further investigations revealed that the family had carried out transactions with the money changer licensee totalling $170 million, but only declared $30 million in transactions.

The department suspected that the money changer had made use of undeclared accounts for laundering purposes.

It has frozen $30 million worth of the family’s assets including the two properties it owned, and revoked the money changer's licence for follow-up investigations.