NEW YORK – U.S. counterintelligence agents have been examining Rudy Giuliani’s business dealings with two men indicted last week on campaign finance charges since at least early 2019, according to a Manhattan lawyer.

Kenneth McCallion, who has represented several Ukrainian clients including former Ukraine Prime Minister Yulia Tymoshenko in U.S. court cases, said the agents contacted him in February or March. They asked whether Giuliani, who is President Donald Trump's personal attorney, had business dealings with Lev Parnas and Igor Fruman.

The Ukrainian-born Parnas and Fruman of Belarus are accused of conspiring to circumvent federal campaign financing laws by funneling foreign money to U.S. political candidates and committees in a scheme to buy influence.

The two men, who now live in Florida, played instrumental roles in connecting Giuliani with Ukrainian officials as Giuliani sought information about the financial dealings there of Hunter Biden, the son of former U.S. Vice President Joe Biden – one of Trump’s 2020 presidential campaign challengers.

Parnas and Fruman were arrested last week as they tried to board a flight out of the country. They're in federal custody on $1 million bonds and have not yet entered pleas to the charges. They are scheduled to appear in a New York City federal court Thursday.

McCallion said he “was asked a lot of questions by FBI and other counterintelligence investigators who were looking at Giuliani’s comings and goings in Ukraine and business dealings.”

"They were interested in the nature of any business dealings with them," McCallion said, referring to Parnas and Fruman.

He said he has not been involved in any business or legal matters with Giuliani.

Giuliani, who has said Parnas and Fruman are his clients, said Tuesday he had "no such knowledge" of a federal inquiry involving him.

Asked whether he was aware that agents had questioned the New York attorney about his dealings with Parnas and Fruman, Giuliani said, "No."

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A person familiar with the matter said federal authorities have been examining Giuliani’s activities as part of the investigation involving Parnas and Fruman,

The person, who is not authorized to comment publicly, did not know whether that inquiry ranged beyond Giuliani’s association with the two men.

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Late last week, The New York Times reported that federal prosecutors are investigating Giuliani for potential lobbying law violations as it relates to his work in Ukraine. The Times reported that the probe focuses on Giuliani's efforts to "undermine" former U.S. Ambassador to Ukraine Marie L. Yovanovitch, who testified before three House committees Friday as part of the House impeachment inquiry of Trump.

The Wall Street Journal reported Monday that investigators have been examining Giuliani’s finances, including bank records related to his work in Ukraine, since at least August.

Tuesday afternoon, Giuliani's lawyer informed House Democrats that he wouldn't comply with a subpoena to produce documents related to his dealings on behalf of Trump in Ukraine.

The committees demanded documents from Giuliani dealing with "the extent to which President Trump jeopardized national security by pressing Ukraine to interfere with our 2020 election and by withholding security assistance provided by Congress to help Ukraine counter Russian aggression."

Giuliani has long-established business in Ukraine

Giuliani has done business in Ukraine since at least 2008. In June 2017, he delivered a speech called “Global Challenge, the Role of the U.S. and the Place of Ukraine,” according to a post on the website of the Pinchuk Foundation.

Victor Pinchuk, a billionaire and the son of a former Ukrainian president, moderated the event and invited future Ukrainian leaders “to shape the proper messages that Mr. Giuliani would bring” to the U.S., the foundation said on its website.

Giuliani met with Ukraine government officials, including then-President Petro Poroshenko and Yuriy Lutsenko, the then-prosecutor general, the post said.

Giuliani subsequently met with Lutsenko in January 2019 in New York and a month later in Warsaw, Poland, according to a whistleblower complaint that has triggered a House impeachment inquiry proceeding against Trump.

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In a series of reports published in The Hill in March and April, Lutsenko and other Ukrainian officials made claims about purported Ukrainian involvement in the 2016 presidential election and former Vice President Biden’s purported efforts to protect Ukraine business interests of his son, Hunter. Neither allegation has been substantiated.

Lutsenko also claimed that Yovanovitch gave him a do-not-prosecute list of subjects in Ukraine. Lutsenko has since recanted that allegation, and several Ukrainian officials have told USA TODAY he's not credible. He has not responded to requests for comment.

Around the same time, Giuliani began to tweet frequently about the Bidens, Ukraine and Yovanovitch.

Parnas and Fruman, according to Ukrainian media reports, helped arrange Lutsenko's New York meeting with Giuliani.

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Feds zeroed in on donation to pro-Trump political action committee

The pair's sizable campaign contributions in the U.S. have attracted the scrutiny of federal election authorities. Their company, Global Energy Producers, was credited with giving $325,000 to a pro-Trump political action committee in May 2018.

That same month, Parnas posted photos on Facebook of him and Fruman with President Trump in the White House and with Donald Trump Jr. in California.

Although Global Energy Partners was identified as the source of the contribution to America First Action SuperPAC, financial records show that the money came via a circuitous route through another company linked to Fruman, according to a federal indictment.

Prosecutors allege that Parnas and Fruman gave $5,400 to a U.S. congressman and pledged to raise another $20,000 as they sought his help in removing Yovanovitch as U.S. ambassador to Ukraine.

That congressman is former U.S. Rep. Pete Sessions, R-Texas, who wrote a letter to U.S. Secretary of State Mike Pompeo urging Yovanovitch's removal.

After Parnas and Fruman were arrested, Sessions said he didn't know about the alleged scheme and would donate their contributions to charity.

Late Tuesday, a spokesman for Sessions said he is cooperating with prosecutors in New York "and will be providing documents to their office related to this matter over the next couple of weeks as requested."

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Attorney General knew about investigation into Parnas and Fruman

Last week, Trump denied knowing Parnas and Fruman, dismissing the photographs and suggesting that reporters refer their questions to Giuliani.

"I don't know them," Trump said. "I don't know about them, I don't know what they do. ... Maybe they were clients of Rudy. You'd have to ask Rudy. I just don't know."

Indeed, until last week, Parnas and Fruman were not household names in the myriad political dramas buffeting Trump’s presidency. But they had been on the radar of federal prosecutors for months.

Shortly after his Senate confirmation in February, Attorney General William Barr was generally alerted to the criminal investigation involving Parnas and Fruman, a Justice official said.

The official, who was not authorized to speak publicly, said Barr was updated in the weeks before the men were arrested, and he was notified last week when they were taken into custody at Dulles International Airport.

It is not clear whether those updates included any discussion about Giuliani’s relationship with the two men.

Contributing: David Jackson, Dennis Wagner