Special prosecutor Robert Mueller zeroed in on President Donald Trump’s business dealings with Deutsche Bank as his investigation into alleged Russian meddling in U.S. elections widens.

Mueller issued a subpoena to Germany’s largest lender several weeks ago, forcing the bank to submit documents on its relationship with Trump and his family, according to a person briefed on the matter, who asked not to be identified because the action has not been announced.

“Deutsche Bank always cooperates with investigating authorities in all countries,” the lender said in a statement to Bloomberg on Tuesday, declining to provide additional information.

Deutsche Bank for months has rebuffed calls by Democratic lawmakers to provide more transparency over the roughly $300 million Trump owed to the bank for his real estate dealings before becoming president. Rep. Maxine Waters of California and other Democrats have asked whether the bank’s loans to Trump, made years before he ran for president, were in any way connected to Russia. The bank previously rejected those demands, saying sharing client data would be illegal unless it received a formal request to do so. Trump has denied any wrongdoing.

Calls and e-mails to the White House weren’t immediately returned.

Mueller’s investigation — which is looking into alleged Russian interference into last year’s U.S. election and whether Trump’s winning campaign assisted in those efforts — appears to be entering a new phase. Trump’s former national security adviser, Michael Flynn, pleaded guilty Friday to lying to FBI agents, becoming the fourth associate of the president ensnared by Mueller’s probe. More significantly, he also is providing details to Mueller about the Trump campaign’s approach to Flynn’s controversial meeting with a Russian envoy during the presidential transition.

Trump’s relationship with Deutsche Bank stretches back some two decades and the roughly $300 million he owed to the bank represented nearly half of his outstanding debt, according to a July 2016 analysis by Bloomberg. That figure includes a $170-million loan Trump took out to finish a hotel in Washington. He also has two mortgages against his Trump National Doral Miami resort and a loan against his tower in Chicago.

Deutsche Bank management is ready to share information about the lender’s dealings with Trump and is hopeful that doing so will help end the series of inquiries from Democrats, an executive at the bank, who asked not to be identified discussing private deliberations, has previously told Bloomberg News.

News of the Deutsche Bank subpoena may escalate Trump’s vitriol toward investigators, which over the past week has included publicly attacking the Justice Department and the Federal Bureau of Investigation, whose reputation he declared to be “in tatters.”

A financial report released Tuesday showed that Mueller’s investigation has cost American taxpayers almost $7 million in its first 4½ months.

Mueller’s team spent $3.2 million directly, the statement shows. The Justice Department, including the FBI, spent another $3.5 million supporting the investigation, with most of that money going toward salaries for prosecutors and investigators and for travel.

The report provides few details into the specifics of Mueller’s work, noting merely that he has spent $1.7 million on personnel, $362,000 for rent and utilities, $733,000 for equipment, $223,000 for travel and $157,000 for contract services, including transcription services. Mueller has hired a team of 17 lawyers. Joshua Stueve, a spokesman for the special counsel, declined to say how many other support staffers were working for him.

 

The New York Times contributed to this report.