(ABC NEWS) -- Special counsel Robert Mueller has issued a subpoena to Germany’s largest bank in a possible sign the investigation into Russian election interference may be expanding toward President Trump’s finances.
Mueller sought records from Deutsche Bank, a source familiar with the subpoena told ABC News.
Specific requests of the bank were not immediately clear but ABC News has previously reported Deutsche Bank loaned the Trump Organization more than $300 million for real estate transactions prior to Trump becoming president.
“Deutsche Bank takes its legal obligations seriously and remains committed to cooperating with authorized investigations into this matter,” a company statement said.
President Trump's legal team confirms it is aware of media reports related to the subpoena, but there was no immediate comment from the White House or the president's attorneys.
In an interview this past July Trump told The New York Times that Mueller would cross a red line if he examined his or his family’s finances.
“I think that’s a violation,” Mr. Trump told the paper. “Look, this is about Russia.”
Deutsche Bank had been one of Trump’s most reliable lenders. ABC News previously reported the bank helped finance the renovation of the Old Post Office in Washington, D.C., the purchase of the Doral golf course in Florida and the construction of an office building in Chicago.
In June Deutsche Bank cited privacy laws when it rejected a request by House Democrats to provide details of Trump’s finances.
Deutsche Bank is not the only Trump-related business interest that is attracting the attention of investigators. Later this week, members of the House Intelligence Committee will be interviewing Felix Sater, a one-time Trump business partner who helped develop the Trump SoHo project.
Mueller is investigating Russian attempts to influence the 2016 U.S. election and any possible collusion by Trump associates. Last week Michael Flynn, Trump's former national security adviser, pleaded guilty to a single count of making false statements to the FBI. Former Trump campaign chairman Paul Manafort, his deputy Rick Gates and former campaign foreign policy adviser George Papadopoulos have also been charged. Papadopoulos pleaded guilty. Manafort and Gates pleaded not guilty.