U.S. Senate investigators are probing a whistleblower’s complaint charging that a political appointee may have “meddled” with an IRS audit of either President Donald Trump’s or Vice President Mike Pence’s taxes, or the returns of both.

Of note is the investigation is bipartisan, and is moving forward, The Washington Post reports.

Investigators are on the staffs of both Senate Finance Committee Chairman Chuck Grassley (R-IA) and Vice Chairman Ron Wyden (D-OR).

Staffers met with the whistleblower last month and follow up interviews are being scheduled.

The whistleblower is identified only as a “career IRS official.”

Last month the whistleblower reportedly said they were “told at least one Treasury Department political appointee attempted to improperly interfere with the annual audit.”

Republican National Committee Chairwoman Ronna McDaniel appears to be enmeshed in an possible pay-to-play scheme, asking a nominee for $500,000 after his ambassadorship nomination ran into trouble.

When the confirmation for President Donald Trump’s ambassador to the Bahamas stalled in the Senate, Republican National Committee Chairwoman Rona McDaniel dashed off an email to the nominee, San Diego billionaire Doug Manchester.

“Would you consider putting together $500,000 worth of contributions from your family to ensure we hit our ambitious fundraising goal?” McDaniel wrote in an email, according to CBS News, which reports the email came “as his confirmation in the Senate hung in the balance.”

Manchester, who had donated $1 million to Trump’s inauguration fund, replied quickly.

“As you know I am not supposed to do any, but my wife is sending a contribution for $100,000,” he wrote. “Assuming I get voted out of the [Foreign Relations Committee] on Wednesday to the floor we need you to have the majority leader bring it to a majority vote … Once confirmed, I our [sic] family will respond!”

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CBS spoke with Manchester, telling him, “You know what this looks like.”

“Well — it looks like it to you. But it’s not the facts,” Manchester responded. “My wife gave out of separate funds and she in fact loves Donald Trump.”

Manchester told CBS it’s just “part of politics.”

“You give and you give and you give and you give some more and more and more,” he said.

He ultimately was forced to withdraw.

This is not the first ambassador nominee who has given huge sums to the RNC or to team Trump. Gordon Sondland, who is at the center of the Ukraine scandal, became Trump’s ambassador to the European Union despite having no experience for the role. He also gave Trump’s inauguration committee $1 million. The New Republic reports many of Trump’s ambassadors are high-dollar donors.

Among them, Kelly Knight Craft, who is now the U.S. Ambassador to the United Nations, “donated $1 million alongside her husband.”

One of Rudy Giuliani’s henchman was carrying items when he was arrested that raise questions about what he was planning as he fled the country.

Lev Parnas, who was arrested with associate Igor Fruman last month on campaign finance violations, was carrying the business card of a Ukrainian prosecutor who had previously met with Giuliani to discuss the conspiracy theories that set in motion the actions now under investigation in the impeachment inquiry, reported The Daily Beast.

Parnas and Fruman were arrested by plainclothes officers last month as they were boarding a jet to Frankfurt on one-way tickets, just hours after having lunch with Giuliani at the Trump International Hotel.

The pair, who investigators say were eventually headed to Vienna, had been enjoying free drinks and food in an airport lounge before their arrest.

Federal agents searched their belongings, and The Daily Beast learned that Parnas was carrying the business card of anti-corruption prosecutor Nazar Kholodnytsky, among 66 items catalogued by FBI agents after the arrest.

It’s not clear how Parnas obtained the card for Kholodnytsky, who had met months earlier with Giuliani in Paris to discuss Joe Biden and his son Hunter and dubious 2016 election interference claims involving Ukraine.

Parnas was also reportedly carrying Trump straws sold on the president’s campaign website, along with large amounts of cash.

Kholodnytsky was caught on a recording earlier this year trying to influence false testimony and tipping off targets to impending raids, although he claims the evidence was taken out of context.

Marie Yovanovitch — who was forced out as the U.S. ambassador to Ukraine following a smear campaign by Giuliani, Parnas and Fruman — called for Kholodnytsky’s removal.

Yovanovitch, who has told lawmakers she felt threatened by President Donald Trump and his associates, will testify Friday in the second public impeachment hearing.