When the dark side of Riggs became known, those who had viewed it positively needed someone external to blame so their own judgement was not called into question. When Riggs management gave evidence to a Senate Committee, a light went on: two targets were presented and, best of all, they were big, foreign, banks that were making inroads into the US banking sector and competing with their own banks abroad. It has taken ten years to build a case to harm the reputation of HSBC.
The Senate Report into Riggs Bank was damning - not just of the bank but of the Office of the Comptroller of the Currency, one of the multiple layers of regulation that covers the US banking sector. The OCC failed to act on deficiencies in the bank's counter-money laundering systems and controls for at least six years, the report said.
But the scandalous aspect, at least so far as it raised the "humph" factor through the roof, was when, in the hearings, a representative of Riggs Bank said that the bank had sought due diligence information from two foreign banks, both of which had said they were unable to release it. The banks were named as Banco Santander and HSBC USA. Santander said that it could not release the information due to strict bank secrecy laws in Spain (a problem that had long been known within the whole banking sector but, because Spain is not regarded in the same light as an "offshore" jurisdiction, no one in authority paid much notice). HSBC USA said that the information sought related to accounts held in Lichtenstein and therefore (no surprises here) the data had to be held secret.
When the report was published in 2004, the reaction to the comments had been moderated: the report says at page 6 :

"An important ancillary issue raised by the Riggs case history involves the ability of U.S. financial institutions with foreign affiliates to get key due diligence information about accounts opened and managed by their foreign affiliates. After questions arose about the $35 million in wire transfers from the Equatorial Guinea oil account, for example, Riggs sent letters under Section 314 of the Patriot Act [SIC] to at least two banks, Banco Santander and HSBC USA, asking them voluntarily to share information about the beneficial owners of certain accounts to which the funds had been directed. These accounts included, for example, ones opened in the name of Apexside Trading Ltd. and Kalunga Co. S.A., at least one of which the Subcommittee has reason to believe may be owned in whole or in part by the Equatorial Guinea President.
"Both banks declined to provide the requested information, because the accounts had been opened at their foreign affiliates in Luxembourg or Spain. Both banks took the position that bank secrecy laws in those jurisdictions barred disclosure of client information by their affiliates, not only to third parties, but also to personnel within the same bank if located outside the host country. This bar on disclosure means, in essence, that banks operating in the United States seeing large wire transfers directed to accounts at foreign affiliates of their own bank cannot obtain key information about the beneficial owners of those accounts, even from their own affiliates. In the Riggs matter, HSBC USA and Banco Santander told the Subcommittee that their own affiliates couldn’t tell them the name of the individuals who owned the companies receiving the multi-million dollar wire transfers, whether those companies were owned by a political figure, or even whether the accounts were still open or had been closed.
"This bar on disclosure across international lines, even within the same financial institution, presents a significant obstacle to effective AML due diligence for banks operating in the United States and a huge impediment to international efforts to stop money laundering, drug trafficking, and terrorism. "