WASHINGTON – It was at the Trump International Hotel.

That's where Rudy Giuliani, the president's personal lawyer, huddled Wednesday with two foreign contacts who had been central to a campaign urging Ukrainian authorities to open an investigation into President Donald Trump’s Democratic rival Joe Biden.

By dinner time, Giuliani’s Ukrainian lunch partners, Lev Parnas and Igor Fruman, were placed under arrest by FBI agents at Dulles International Airport, as they clutched one-way tickets to Frankfurt, Germany.

What has since spilled from federal authorities and court documents are details of a tangled criminal inquiry highlighting the efforts of Parnas and Fruman to funnel huge caches of foreign money to U.S. political campaigns – a troubling narrative that now intersects with Congress’ fast-moving inquiry into the impeachment of the president.

While neither the president nor Giuliani were named in the new campaign finance case Thursday, the four-count indictment was unsealed as three House committees had scheduled depositions this week with Parnas and Fruman to learn how they may fit – if at all – in Trump’s personal push this summer for Ukraine President Volodymyr Zelensky to investigate Biden and his son, Hunter.

Trump late Thursday denied any involvement with the two men, brushing aside photographs posted on social media last year showing both men with Donald Trump Jr., and Parnas with the president, describing an “incredible dinner and even better conversation.”

'I don't know those gentlemen':Trump denies knowing indicted Giuliani associates despite photos

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“Now, it’s possible I have a picture with them because I have a picture with everybody,” Trump said. “I don’t know about them. I don’t know what they do. … Maybe they were clients of Rudy. You have to ask Rudy. I just don’t know.”

Giuliani declined to comment when reached by USA TODAY, but his association with Parnas and Fruman has brought new potential trouble to the doorstep of the White House, as Trump already is battling the greatest threat to his presidency in the form of the Democrat-led impeachment inquiry.

Parnas, Fruman drew scrutiny

Even as Parnas and Fruman were drawing the scrutiny of Congress for arranging a January meeting in New York between Giuliani and Ukraine's then-prosecutor general, Yuri Lutsenko, as part of the campaign to launch an investigation into the Bidens, federal prosecutors in New York were taking aim at the pair for their suspicious movement of money to political campaigns in the U.S.

What happened:Biden, allies pushed out Ukrainian prosecutor because he didn't pursue corruption cases

According to court documents unsealed Thursday, the dual interests of the Giuliani associates sometimes overlapped.

Among the beneficiaries of their largess, prosecutors allege, was a U.S. congressman who received $5,400 last year from the pair, who also pledged to raise $20,000 for the lawmaker as they sought to enlist him in an effort to remove Marie Yovanovitch as U.S. ambassador to Ukraine.

In his July 25 call to Zelensky, Trump makes an apparent disparaging reference to Yovanovitch, suggesting that she was ultimately recalled for criticizing the president. During the same call, he urged the Ukrainian president to work with Giuliani and U.S. Attorney General William Barr to assist in the investigation of the Bidens.

A visual timeline:The events that led up to Trump's fateful phone call

The congressman who received the political donations was not named in court documents, but a person familiar with the matter identified the lawmaker as former Rep. Pete Sessions, R-Texas.

Sessions wrote Secretary of State Mike Pompeo last year, urging the ouster of Yovanovitch, who was recalled in May.

Ukraine:Trump's conspiracy theories thrive in Ukraine, where a young democracy battles corruption and distrust

Parnas and Fruman, however, made their biggest political splash last year when their company, Global Energy Producers, was credited with giving $325,000 to the committee that supports Trump's re-election, America First Action SuperPac.

The campaign contribution sparked a complaint to the Federal Election Commission–and at least two lawsuits – because of questions about the source of the money. Citing the contribution Thursday, Manhattan U.S. Attorney Geoffrey Berman, who announced the campaign finance charges, characterized the suspicious donation as one of the largest that the committee had received.

America First acknowledged on Thursday receiving the donation, adding that the committee also was aware of the FEC complaint.

"Accordingly, America First Action placed that contribution in a segregated bank account, it has not been used for any purpose and the funds will remain in this segregated account until these matters are resolved," the committee said in a statement.

Trump in Minnesota:Trump lashes out at Democrats over impeachment inquiry at Minneapolis rally

Arrested, then subpoenaed

As the criminal case was unfolding against Parnas and Fruman on Thursday, Congress also was pursuing them as witnesses in the impeachment inquiry.

Both men were scheduled to appear before the House Oversight, Intelligence and Foreign Affairs committees. Parnas had been scheduled Thursday and Fruman was slated to appear Friday.

Turning up the heat, House Democrats issued subpoenas for the two men just hours after their arrests.

"Your clients are private citizens who are not employees of the Executive Branch," the chairmen of the House committees wrote to attorneys for Parnas and Fruman. "They may not evade requests from Congress for documents and information necessary to conduct our inquiry."

The arrests:Giuliani associates, linked to Ukraine controversy, arrested on campaign finance charges

The subpoena demands documents related to Ukraine by Oct. 16. It does not outline an exact date for the men to appear before the panels, saying only that "the committees also expect your clients to appear to testify about these matters at a later date."

By Thursday afternoon, however, Parnas and Fruman, whose Wednesday lunch with Giuliani was first reported by the Wall Street Journal, were in no position to tend to Congress' demands.

During a brief federal court hearing in Alexandria, Virginia, a judge set bail at $1 million for each defendant, demanding that both submit to electronic monitoring before they would be released from custody. The case is likely to move to a federal court in New York, where the charges were first filed Thursday.

Before the day's end, however, New York FBI chief William Sweeney and Berman – a Trump appointee – sounded a decidedly ominous note, saying that the investigation had not ended with with the arrests of Parnas and Fruman.

"This investigation is about corrupt behavior and deliberate law breaking," Sweeney said before both officials abruptly left a New York stage without taking questions.

The subpoenas:Impeachment: Lawmakers subpoena Giuliani associates Lev Parnas and Igor Fruman, hours after their arrests