The Russia-related probes haunting Donald Trump's presidency are being pushed into a dark new realm: the president's political tormentors are now asking questions about the underworld, organized crime, and money-laundering. This recent development has been overshadowed by other daily headlines like the latest news about Trump's son-in-law Jared Kushner allegedly seeking a secret communication channel with the Russian government. But investigators have made clear they're following a money trail.

Both parties have begun asking for Trump-related financial records, with the Democrats being more vocal about it: last week lawmakers from that party issued separate letters to the Treasury Secretary and to Deustche Bank demanding documents. "The nearly constant stream of allegations about the President's ties to Russian government officials, oligarchs and organized crime leaders raises serious questions as to whether such individuals may have financial leverage over the President and his administration," said the letter to Treasury Secretary Steve Mnuchin. It requested documents related to foreign loans to Trump; certain transactions at his casinos; real-estate investments; and records from banks including VneshEconomBank, the one currently under U.S. sanctions which Kushner met with after the election. That means investigators are looking way farther back than Wikileaks and email hacks as they examine the story of alleged Russian meddling in the 2016 U.S. election. "We have to follow the money if we are going to get to the bottom of how Russia has attacked our democracy," Ron Wyden, who is involved in one of several congressional investigations, said this month in the Senate.

"(We must) thoroughly review any information that relates to financial connections between Russia and President Trump and his associates, whether direct or laundered through hidden or illicit transactions." One source of interest is an anti-money-laundering unit within the U.S. Treasury Department, known as FinCEN. Lawmakers have requested financial data from it, have received some, and are seeking more. This same unit twice fined a Trump casino for what it called a chronic, wilful, and long-term failure to implement anti-money-laundering safeguards, resulting in a historically high federal penalty of $10 million against Trump Taj Mahal in 2015. It's not the only time Trump's financial activities have drawn unwanted attention. He has repeatedly downplayed his connections to the Bayrock Group. According to various media reports, Bayrock, an investor in major Trump projects, was linked not only to an accused money-launderer from Kazakhstan, but had as a senior official a Russian-born, twice-convicted ex-mobster; Felix Sater had done time for stabbing a man in the face with a broken margarita glass, then was indicted as part of a Mob-run financial scheme. Authorities have a duty to examine all of this, said an internationally renowned expert on money-laundering. "This is just too many unanswered questions. It is just too important to leave it hanging there, and resolve it with a tweet or a short piece," said Nikos Passas, a professor at Northeastern University who has advised different governments and international organizations, and testified before the U.S. Congress. "This is in fact an important set of questions, about the integrity of the office. It is not even a domestic matter. It is an international security matter. You cannot leave that hanging."

He said real estate is vulnerable to exploitation. As for the casino penalties, Passas said FinCEN's role was to gather data on suspicious activity reported by banks; it supplies documents for police investigations and can also, as in the case of Trump Taj Mahal, hand out fines. Lawmakers from both parties have requested FinCEN documents — and received some. However, Democrats are expressing frustration that they haven't yet managed to receive others. The opposition party has attempted to speed up the delivery of documents, by delaying a senior appointment to the Treasury Department which runs FinCEN.

There are concerns in Washington that all the ongoing investigations might start interfering with each another. At least five are underway. They include a law-enforcement probe led by the former head of the FBI, Robert Mueller, who has been appointed as a special counsel, while the Senate and House intelligence committees, the Senate judiciary committee, and the House oversight committee examine aspects of the Russian affair. Some big players are under the microscope. They include: —Trump's first national-security adviser Michael Flynn. During his background check for the senior position, he failed to disclose payments of more than $45,000 from Russia's state-run TV network RT, and $530,000 from a Turkish-owned consulting firm, in addition to allegedly misleading colleagues about some contacts. Asked by lawmakers to produce documents, Flynn refused, citing his Fifth Amendment right not to incriminate himself. Lawmakers are weighing whether to charge him with contempt of Congress. Republican James Lankford of Oklahoma told CNN this week: "Businesses are not protected by a Fifth Amendment. Individuals are." —Trump's former campaign manager has turned over business records to the Senate intelligence committee. A longtime political consultant for the pro-Kremlin party in Ukraine, Paul Manafort's financial transactions are under investigation according to multiple reports. —Trump's son-in-law and staffer, Kushner, has also drawn authorities' attention, according to different reports. These reports say their interest was piqued by Kushner's interactions with Russia's ambassador, and the sanctioned bank. Kushner did not disclose those meetings on the legal forms he filled out as he entered the White House. A new report in the Washington Post, later corroborated by the New York Times, cites sources saying Russia's ambassador reported back to Moscow that, last December, Kusher suggested setting up a private communication line to avoid U.S. federal scrutiny. Prior to that latest report, his lawyer Jamie Gorelick had stated: "Mr. Kushner previously volunteered to share with Congress what he knows about these meetings. He will do the same if he is contacted in connection with any other inquiry."