The U.S. Securities and Exchange Commission is investigating bankrupt Ally Financial mortgage unit Residential Capital, LLC, for possible misconduct and misrepresentation in its mortgage lending and underwriting practices.

The SEC disclosed in court documents on Monday that it formerly commenced an investigation in February of this year to probe possible fraud in the offer and sale of mortgage-backed securities by ResCap. The agency was forced to reveal the existence of the investigation in order to compel R.R. Donnelley & Sons to turn over due diligence reports that its wholly-owned subsidiary, Office Tiger Global Real Estate Services, prepared for the investment banks that underwrote the troubled securities.

The SEC claims it needs the reports to determine whether ResCap violated federal securities laws by making “material misrepresentations or omissions about the mortgage loan pools that backed the securitizations under investigation.”

Specifically, the SEC “is investigating ResCap’s origination and underwriting practices used to make and approve loans in connection with offerings of residential mortgage backed securities, and the creditworthiness of borrowers on loans underlying offerings of residential mortgage backed securities.”

The SEC subpoenaed the due diligence reports from R.R. Donnelly in June, but the company refused to fully comply with the subpoena, citing privacy concerns arising from the Right to Financial Privacy Act, 12 U.S.C. § 3401, et seq. In its motion to compel, the SEC argues that R.R.Donnelly is neither a financial institution nor an agent of a financial institution, and as such, the company is not subject to the RFPA.

Moreover, because the agency’s investigation is directed at ResCap and not ResCap’s customers, the subpoena falls outside the scope of the RFPA. The court has not yet ruled on the merits of the SEC’s motion.

The case is Securities & Exchange Commission v. Custodian of Records, R.R. Donnelly & Sons, Co., Case Number CV12-7331-SVW, United States District Court, Central District of California.