Do the Russians have something on Donald Trump? The question has been asked since the early days of Trump’s Presidential campaign, in an attempt to make sense of his vocal admiration for Vladimir Putin, and his advocacy for improved relations with the Kremlin. It’s possible, of course, that the answer is no. Trump is an instinctive authoritarian, and he may simply, genuinely admire Putin, and see in him a potential ally for the United States’s global efforts against Islamic extremism.

Yet the question has lingered into Trump’s Presidency. One theory, propounded in the opposition research dossier put together by a former British spy named Christopher Steele, is that the Russian government collected damaging material about Trump—including a sex tape—during his business trips to the country. Trump has dismissed the dossier’s assertions as nonsense. Another theory holds that it’s all about money, and that Trump is somehow in hock to Russian lenders or investors linked to the Kremlin. Back in January, Donald Trump explicitly denied this in a tweet, resorting to his trademark all-caps style of communication. “Russia has never tried to use leverage over me,” he wrote. “I HAVE NOTHING TO DO WITH RUSSIA—NO DEALS, NO LOANS, NO NOTHING.”

But the suspicions haven’t gone away. In an interview earlier this year, Sir Richard Dearlove, a former head of Britain’s spying agency, MI6, said, “What lingers for Trump may be what deals—on what terms—he did after the financial crisis of 2008 to borrow Russian money when others in the West apparently would not lend to him.” Dearlove didn’t provide any evidence to support this theory. Nobody else has, either, although not for the want of trying. A number of news organizations have dispatched reporters to Iceland, Cyprus, and other jurisdictions through which hot money can flow anonymously. So far, these journalistic diggers have failed to identify any hidden Russian lenders to the Trump Organization.

At the same time, though, numerous reports have detailed how funds from wealthy Russians and citizens of other former Soviet states have flowed into ritzy Trump-owned or Trump-branded real-estate properties, such as the Trump SoHo building, in New York, and the Trump International Beach Resort, in Florida. (Last month, the owner of Trump SoHo announced that the Trump Organization would no longer be involved with the property.) The Washington Post has revealed how, as recently as late 2015 and early 2016, when Trump was already running for President, a Russian-born business associate of his, Felix Sater, was “pursuing a plan to develop a massive Trump Tower in Moscow.” And The New Yorker’s Adam Davidson has shown how Trump and his family entered into partnerships with politicians and oligarchs in Azerbaijan and Georgia, two countries with close ties to Russia.

Enter Robert Mueller, the special counsel investigating Russia’s meddling in last year’s election. On Tuesday, the German newspaper Handelsblatt and other media outlets reported that Mueller’s office has demanded financial records from Deutsche Bank, a large German bank that is one of the biggest lenders to companies associated with Trump, and that has also had controversial ties to Russia. The news reports said that Mueller’s office issued a subpoena to the bank earlier this fall; the impression was that the bank, despite its public refusal to confirm any details, was willingly coöperating with the investigation.

As the day wore on, the details of the story got somewhat muddied. Some of the early reports said that Mueller had asked Deutsche for information about accounts held by the President and members of his family. In statements to reporters, Trump’s lawyers—Ty Cobb, John Dowd, and Jay Sekulow—insisted that these reports were inaccurate. They claimed that no subpoena had been issued to Deutsche. Late Tuesday, the Wall Street Journal issued a partial correction of its initial story, dropping the claim that Mueller’s subpoena directly concerned Trump and his family members. But the Journal stood by the substance of its report, saying that the subpoena “concerns people or entities close to Mr. Trump.” On Wednesday, Handelsblatt also reaffirmed its story. “Yes, Deutsche did get a subpoena from Mueller,” the paper stated in a headline.

Since Deutsche and Mueller’s office have both refused to comment publicly, there is no way to know exactly what information the special counsel’s office has asked for, but Trump’s dealings with Deutsche have been extensive. “Since 1998, the bank has led or participated in loans of at least $2.5 billion to companies affiliated with Mr. Trump,” the Journal reported, in a lengthy piece published in March, 2016. “That doesn’t include at least another $1 billion in loan commitments that Deutsche Bank made to Trump-affiliated entities.”

Despite these extensive dealings, the relationship between Deutsche and Trump has sometimes been rocky. In 2008, after Trump missed a loan payment on the Trump International Hotel and Tower in Chicago, the two sides ended up suing each other, and Deutsche’s investment bank stopped working with him, according to the Journal. But Deutsche’s private-banking division subsequently stepped in, “lending well over $300 million to Trump entities in the following years.”

The German bank is said to be keen to coöperate with Mueller in order to clear its name as it has already been under scrutiny for its role in a Russian money-laundering scandal, which involved bank employees in Moscow and London setting up “mirror trades,” and which enabled rich Russians to move about ten billion dollars out of their country between 2011 and 2014. It has been reported that Deutsche has already carried out an internal investigation into its ties to Trump and found nothing suspicious. However, citing client-confidentiality requirements, the bank has balked at providing internal records to congressional investigators. “Deutsche could not hand over client information without a subpoena,” a source close to the bank told the Financial Times. “It’s helpful to be ordered to do so.”

That might provide some reassurance for the President’s lawyers, but it hardly seems likely to assuage Trump himself, who in June told the Times that he would regard Mueller delving into his personal finances unrelated to Russia as “a violation” of his job mandate. “Look, this is about Russia . . . I have no income from Russia. I don’t do business with Russia,” Trump said.

Actually, the special counsel’s remit is a broad one. According to the order that Deputy Attorney General Rod Rosenstein issued when he appointed Mueller, in May, he is authorized to investigate “any links and/or coordination between the Russian government and individuals associated with the campaign of President Donald Trump” and “any matters that arose or may arise directly from the investigation.” According to Handelsblatt’s reporting, Mueller’s subpoena requires Deutsche to provide information on certain “financial transactions and loans.” If that is true, it strongly suggests that the special counsel’s team is following up specific leads rather than conducting a fishing expedition.

Whether these inquiries will lead anywhere remains an open question. One thing seems clear, though: Mueller’s investigators are following Deep Throat’s advice and following the money. For Trump and his associates, that has to be disturbing.