The London-based, multinational bank HSBC faces a strong legal backlash after a massive leak revealed that the bank’s Swiss branch allowed and helped American clients dodge taxes, reported The Guardian.

According to the leaks, released by a former HSBC IT employee, the bank actually encouraged and informed some clients on “how to circumvent domestic tax authorities.” HSBC conspired with clients to “conceal undeclared ‘black’ accounts from domestic tax authorities across the world.” Simply put, HSBC enabled illegal banking activities. The bank also held money for international criminals.

“Banks can’t be left to their own devices to do what is in the best interest of their clients,” commented Peter Mougey, a partner with the Levin, Papantonio law firm  and director of the firm’s business torts and securities litigation departments.

The United States Department of Justice and the Internal Revenue Service face mounting pressure to act now that this evidence has surfaced. Reuters reported that American authorities have increased their investigatory efforts in determining HSBC’s true role in helping wealthy American clients dodge taxes.

HSBC’s shadowy behavior reflects a 2012 deferred prosecution where the bank agreed to pay $1.9 billion to settle allegations that the bank held and moved millions for international drug lords. These new allegations might elicit the DOJ to revisit the 2012 deal.

“It is quite possible that the (agreement) may be reopened as a result of the bank’s activities on either or both the tax evasion and foreign exchange manipulation front,” said a US official.

Included within the documents was a list of clients that HSBC assisted in their tax evasion. The list includes Morocco’s King Mohammed, tennis players, Hollywood celebrities, international arms dealers, people connected to former dictators and conflict diamond traffickers. The actual method in which HSBC helped these people move money is something straight out of a Martin Scorsese film.

According to The Guardian, HSBC allowed these clients to withdraw “bricks” of cash in a currency that’s otherwise useless in Switzerland. The client could then send portions of the “brick” home in amounts smaller than what was legally required to declare. Clients were able to incrementally move large amounts of money tax free.

HSBC is the second-largest bank in the world, and it actively helped its clients break the law and dodge taxes. The answer isn’t a billion-dollar settlement. That’s chump-change to the likes of HSBC. Executives need to be tried, thrown in jail, and be barred from the banking industry.