Attorney General Martha Coakley has expanded the scope of her investigation into the mortgage mess, requesting info from London-based HSBC on sales of residential mortgage backed securities.

The bank disclosed the request in its annual filings with the Securities and Exchange Commission, saying that the bank had received a request in January for "documents, information and testimony related to the sale of RMBS [residential mortgage-backed securities] to public and private customers in the State of Massachusetts from January 2005 to the present."

An HSBC spokesman declined to comment on the matter beyond what was disclosed in the filings.

Coakley announced earlier this month that she would be participating in the Residential Mortgage-Backed Securities Working Group, a federal-state effort to investigate problems with the sale of mortgage securities announced by President Obama in his State of the Union address last month. 

A spokesman for the attorney general’s office said the request was unrelated to Coakley’s participation in the task force. Coakley has previously filed suit against several Wall Street banks over improprieties related to securitization, including the Royal Bank of Scotland, Goldman Sachs and Morgan Stanley, winning over $200 million in settlements.