When thinking about Donald Trump’s monetary dealings with Russia, it’s easy to think of them as being part of his past. Sure, he sold a Florida home to an oligarch for $100 million—well over twice its value. And, when his business was essentially bankrupt for the seventh time and no bank would give him a loan, Trump collected enough money from Russian mobsters for his rich guy act to continue. But that was … when was that?

Since Election Day, President Trump’s businesses have sold at least 30 luxury condos and oceanfront lots for about $33 million. That includes millions of dollars in properties to secretive shell companies, which can hide the identities of buyers or partners involved in the deals, a USA TODAY investigation has found.

Shell corporations, like those set up by friend of a friend Irakly "Ike" Kaveladze, who was the eighth man at that infamous Trump Tower get together. Kaveladze was there to represent Russian real estate family the Agaralovs. Before he became part of their operation to lobby Trump over the Magnitsky Act, Kaveladze had another job. He helped create more than 2,000 shell companies—most of which went right back to Aras and Emin Agaralov.

The use of shell companies by investors, added to the over 500 shell companies used by Donald Trump, can make the real actors behind real estate transactions hard for state and local officials to see without help. But they could be getting that help.

Details of some of those deals and other transactions by Trump's family business could be unmasked as special counsel Robert Mueller expands his inquiry into election-meddling by Russia and whether Trump's campaign colluded.

Which is why Trump is in a big, big hurry to stop Mueller.

There’s a point in every episode of Perry Mason where Perry pins a witness on the stand with the question “do you know what the penalty for perjury is in this state?” On television, witnesses fold in the face of threat. In real life, they know well enough that perjury is no big deal if the alternative is being found guilty of something much worse.

For Donald Trump, firing Robert Mueller may seem to have dire political consequences. But anyone shaking a finger in his direction with the suggestion that firing Mueller would be bad should consider that what Mueller finds could have a lot more impact than making Chuck Grassley frown.

Federal investigators are expected to delve into records revealing some of the President’s most closely guarded secrets, including how much money he makes, who he does business with and how reliant he is on wealthy, politically-connected foreigners.

A half-dozen experts contacted by USA TODAY said they expect Mueller and his team to pursue everything from Trump’s income tax returns to the bank records underlying his companies’ real estate transactions in a quest to identify people who have financial relationships with the President and his business and political associates.

Donald Trump isn’t desperate to stop Mueller because he’s worried about being embarrassed. It’s as easy to scream “fake investigation” as it is to shout “fake news.” He’s worried about the connections Mueller will find—connections that may still be funneling money to the Trump Organization from it’s supporters … overseas.

Trump’s real-estate business in particular has relied on wealthy Russians and other foreigners, sometimes as buyers of condos in the company's towers around the world and as investors or partners in the projects.