The Federal Reserve’s involvement in the controversial merger between Bank of America (BAC) and Merrill Lynch is yet to be determined, but a memo circulating among Congressional Republicans may suggest a bigger role than previously acknowledged.

Some House Republicans are saying the Federal Reserve tried to control the release of Merrill’s rising losses ahead of the merger with Bank of America.

The memo, which cites documents and Fed e-mails, has been viewed by member of the House Oversight and Government Reform Committee. 

Federal Reserve Chairman Ben Bernanke is schedule to testify on Thursday and respond to questions from that committee whether he directly threatened to fire Bank of America’s management, and whether the threat was an appropriate use of government authority. 

Sources familiar with the documents obtained by the committee quoted the memo as stating, “On April 23, New York State Attorney General Andrew Cuomo sent a letter to members of Congress in which he alleged that (Bank of America CEO) Ken Lewis, under duress from the Treasury and the Federal Reserve, may have violated his fiduciary responsibility to Bank of America’s shareholders in the interest of the larger U.S. financial system.” 

The allegations stemmed from an investigation in which Lewis seemed to admit to Cuomo’s investigators that, under government pressure, he consented to a merger with Merrill that was not in the best interests of his own shareholders.

The memo continued:  “Bernanke, Treasury Secretary Henry Paulson and Lewis have all taken great pains to deny that the government pressured Bank of America or Merrill Lynch to violate federal securities laws by not disclosing material information to their shareholders. Internal emails reveal at least the intent to influence disclosure decisions in order to allow the government to manage the situation.”