Of all the things Donald Trump has chosen to do differently than any other president before him, his refusal to release his tax returns has struck many as the most curious.

Initially, Trump insisted that he was under audit, but the IRS said that even under audit, his releasing his tax returns would not be a problem.

Then it was that they were too complicated for anyone to understand.

That morphed into, “Nobody cares.”

Now it seems, he’s moved on to, “OMG… THEY’RE GOING TO LOOK AT MY TAX RETURNS!”

That was the report late Thursday, when the news turned to special counsel Robert Mueller’s investigation expanding to look into Trump’s business dealings.

According to Bloomberg:

The U.S. special counsel investigating possible ties between the Donald Trump campaign and Russia in last year’s election is examining a broad range of transactions involving Trump’s businesses as well as those of his associates, according to a person familiar with the probe.

FBI investigators and others are looking at Russian purchases of apartments in Trump buildings, Trump’s involvement in a controversial SoHo development in New York with Russian associates, the 2013 Miss Universe pageant in Moscow and Trump’s sale of a Florida mansion to a Russian oligarch in 2008, the person said.

The investigation also has absorbed a money-laundering probe begun by federal prosecutors in New York into Trump’s former campaign chairman Paul Manafort.

That’s a pretty deep probe.

Trump, in an interview with the New York Times on Wednesday, had said that if Mueller started digging into information beyond the 2016 election, it would be crossing a line.

By Thursday, Mueller hadn’t just crossed the line, but it appears he soaked it in kerosene and lit a match.

All that being said, the scope of Mueller’s investigation was given pretty wide territory.

The Justice Department’s May 17 order to Mueller instructs him to investigate “any links and/or coordination between the Russian government and individuals associated with the campaign” as well as “any matters that arose or may arise directly from the investigation,” suggesting a relatively broad mandate.

Agents are interested in dealings with the Bank of Cyprus, where Wilbur Ross served as vice chairman before he became commerce secretary. In addition, they are examining the efforts of Jared Kushner, the President’s son-in-law and senior aide, to secure financing for some of his family’s real-estate properties. The information about the investigation was provided by someone familiar with the developing inquiry but not authorized to speak publicly.

The roots of Mueller’s follow-the-money investigation lie partly in a wide-ranging money-laundering probe launched by then-Manhattan U.S. Attorney Preet Bharara last year, according to the person.

Bharara was fired back in March.

There has also been recent reports that Trump has at least broached the topic of his powers of pardon, although those reports are framed in the context of casual curiosity, and not as if he were addressing this investigation, specifically.

Whatever the case, Trump is not pleased with the news of Mueller’s expanding investigation.

We can only speculate why.