While everyone wrestles with the news that former Trump campaign chairman Paul Manafort was the subject of a government wiretap (and no, this doesn’t mean Trump was wiretapped), the investigation into Russian interference in the 2016 election rolls on.

Next up to bat is Donald Trump’s longtime personal attorney, Michael Cohen.

Cohen appears today before the Senate Intelligence Committee in a closed-door session to testify, presumably, about Trump’s business ties to Russia.

Cohen is seen as a key figure in the myriad investigations into election meddling, thanks both to his work on a proposed Trump Tower deal in Moscow and his appearance in a shadowy, unconfirmed dossier full of incendiary allegations about Trump and Russia.

The interview with staff on the Senate Intelligence Committee, which is expected to take place behind closed doors, will not be under oath, but witnesses nevertheless face criminal charges for misleading congressional committees.

Cohen has also served as an executive with Trump’s organization, and his closeness to Trump is keeping him firmly in focus, as the investigation moves forward.

Cohen’s name appears in numerous allegations in the document, including an alleged secret meeting with Kremlin officials in August 2016 in Prague.

The dossier also claims that Cohen was deeply involved in a “cover up and damage limitation operation in the attempt to prevent the full details of Trump’s relationship with Russia being exposed.”

Parts of the dossier seem to contain inaccurate information, but there’s still enough meat on that bone for investigators to chew on, and that’s what investigators intend to do. They feel that even though there is questionable points, there are also clues and prompts that need to be followed up.

Cohen’s attorneys have sent a point-by-point denial to investigators, regarding the dossier. It’s not just the dossier that has Cohen neck-deep in this investigation, however.

During the Trump campaign, Cohen had a part in attempting to push forward a development project between Trump’s business and Moscow.

In January of 2016, he emailed Russian President Vladimir Putin’s personal spokesman to ask for help with speeding along languishing negotiations, according to emails reported by The Washington Post.

The revelation of the request — perhaps the most well-documented confirmation yet of a direct interaction between a senior Trump aide and a senior Putin aide — comes as Trump’s business ties to Russia continue to be under intense scrutiny.

But at the time, Cohen had been in negotiations with Felix Sater, a Russian-American businessman who was serving as a broker for the Trump Organization, to attempt to build a Trump Tower in the Russian capital.

The project was envisioned as a licensing deal, in which a Moscow-based developer would have paid Trump for the use of his name. Trump signed a letter of intent with the developer in October 2015, according to The Post.

Sater had boasted that the deal would help Trump’s campaign. At the time, Trump had already announced his candidacy and the GOP primaries were well under way.

The deal fell through and Cohen is playing it off as a routine licensing venture.

Still, for something so minor, in his estimation, Cohen has avoided speaking to congressional investigators.

“We believe the allegations are so profoundly wrong about Mr. Cohen that the dossier is libelous and any repetitions of its allegations by the committee should be rejected,” Cohen’s lawyer wrote in the August letter to the House committee, published by The Daily Beast.

It’s unclear how much information he will be required to disclose to investigators. He could claim attorney-client privilege during the interview — and in fact, may be obligated to, unless Trump waives the privilege, according to Bradley Moss, a lawyer who specializes in national security.

I can just about guarantee that’s not going to happen.

How much information is gathered today may very well depend on Cohen’s comfort level. For now, he’s just one more piece in the puzzle.