In the final year of the Obama administration, an American lawyer traveled to Romania to meet with a businessman accused of orchestrating a corrupt land deal.

The businessman was Gabriel “Puiu” Popoviciu, a wealthy Romanian real estate tycoon. The lawyer brought in to advise him was Hunter Biden, the son of then-Vice President Joe Biden, according to two people familiar with the matter.

Hunter Biden’s work for Popoviciu in 2016 went unreported at the time, but Joe Biden’s involvement in Romania was very much public. The vice president was among the leading voices pushing the government to crack down on corruption.

Download the NBC News app for breaking news and politics

There’s no evidence that Hunter or his father acted improperly or violated any laws. But the arrangement, government ethics experts say, raises concerns that Hunter Biden was used as a prop in Popoviciu’s effort to dodge criminal prosecution.

“We don’t know what [Hunter Biden] was paid or what he was paid for but it does raise questions of whether this Romanian individual facing criminal charges was actually paying for a connection to the American vice president,” said Kathleen Clark, a Washington University law professor who specializes in government ethics.

Hunter Biden’s work overseas — primarily in the Ukraine and China — has become a subject of the presidential campaign through the efforts of Trump and his personal lawyer Rudy Giuliani to portray the international dealings as corrupt. In July, Trump urged the Ukrainian president to launch an investigation of Biden related to his son’s work for a Ukrainian gas company, according to a White House notes on the call, triggering the impeachment inquiry underway in the House.

Giuliani and Trump have provided no evidence, and no proof has emerged of any wrongdoing by Hunter or his father.

But last week, Hunter Biden announced that he will step down from the board of a Chinese investment company that he joined in October 2017. And in an interview with ABC News released last Tuesday, he acknowledged showing “poor judgment” but denied any ethical lapses in taking a position on the board of the Burisma gas company in Ukraine at a time when his father was leading American policy in the country.

Hunter Biden’s activities related to Romania have gotten far less attention.

The case against Popoviciu was set in motion in 2005 when a businessman lodged a criminal complaint against him and the rector of a Romanian university relating to the sale of a 550-acre plot of land near Bucharest, according to documents from the European Court of Human Rights.

The businessman claimed Popoviciu had purchased the land for “significantly less money than it was actually worth,” the documents say. Further, the businessman alleged the plot wasn’t the property of the University of Agronomy, but was instead owned by the Romanian government, according to the documents.

Romanian prosecutors initially declined to investigate citing a lack of evidence. But in July 2008, the country’s National Anti-Corruption Protection Service took over the case.

The university rector was charged in March 2009 with abusing his position and Popoviciu was charged with “complicity in abuse of position,” the documents show. Two months later, Popoviciu was hit with a bribery charge.

Popoviciu was convicted in 2016 but launched an appeal. He assembled a high profile legal team to fight the conviction, which included former FBI director Louis Freeh, according to a release from Freeh’s firm.

That same year, Hunter Biden traveled to Romania to assist Popoviciu, according to two people familiar with the matter. The New York Times was first to report on the younger Biden’s involvement in Popoviciu’s case.

At the time he was brought in, Hunter Biden was performing work for the law firm Boies Schiller Flexner LLP where he was “of counsel.” The firm did not respond to a request for comment.

Romania was by then a familiar place to the Biden family. A close friend and former staffer of Joe Biden, Mark Gitenstein, held the position of U.S. ambassador to Romania from August 2009 to December 2012. In March 2012, Hunter’s brother, Beau, was asked to do the ribbon-cutting at the new U.S. embassy in Bucharest.

Vice President Biden visited Romania in 2014 and delivered a forceful speech against graft. “Corruption is a cancer, a cancer that eats away at a citizen’s faith in democracy,” he said. “Corruption is just another form of tyranny.”

It’s unclear how much assistance Hunter Biden provided in Popoviciu’s case. The Romanian real estate tycoon’s bid to overturn his conviction ultimately failed. He was sentenced to seven years in prison in August 2017, according to a press release from Freeh’s firm.

Romanian police officers showed up at Popoviciu’s home to take him into custody on Aug. 2, but he was nowhere to be found and soon declared a fugitive, according to the news site romania-insider.com.

Popoviciu was arrested in London days later.

Freeh continued working on behalf of Popoviciu. Last year, he tapped Giuliani, his longtime friend, to assist in his Romanian work.

Giuliani’s hiring created what appears in hindsight a strange-bedfellows arrangement. Giuliani, who has been the loudest critic of Hunter Biden’s work in the Ukraine, was working on the same side as the younger Biden in Romania.

In August 2018, Giuliani wrote a letter to Romania’s president and prime minister criticizing the country’s recent efforts to rein in corruption as overly aggressive. Giuliani’s position contradicted the U.S. stance on anti-corruption efforts in Romania.

It wasn’t until several months later that Giuliani began publicly assailing Hunter Biden for his work in Ukraine and pushing the unsubstantiated allegation that his father helped to force out a prosecutor to end a probe into the gas company that employed Hunter.

Last month, Giuliani indicated that he was planning to broaden the line of attack against Hunter Biden.

“We haven’t moved to Romania yet. Wait ‘til we get to Romania,” Giuliani told Fox News host Howard Kurtz.

When NBC News asked Giuliani to elaborate on his claims about Hunter Biden relating to Romania, he offered a terse response. “I only know rumors about it,” Giuliani said.

Popoviciu, who is still in London, is fighting extradition to Romania, according to U.K. officials. His lawyer did not return a request for comment.

Robert Weissman, president of Public Citizen, a nonprofit government watchdog group, said that “it’s hard to avoid the conclusion” that Hunter Biden secured his overseas positions because of his name.

But Weissman said his conduct pales in comparison to that of the Trump family, which has been accused of using the office of the president to enrich their businesses. The president's daughter Ivanka Trump, for instance, pulled in almost $4 million in revenue last year from her stake in the family hotel near the White House.

“The issues raised by Hunter Biden are orders of magnitude less corrosive than the everyday wrongdoing by Donald Trump and his children including his interactions with foreign governments and overseas revenue streams,” Weissman said.

Hunter Biden’s lawyer, George Mesires, didn’t respond to a request for comment when asked about his client’s work in Romania. In the ABC News interview, Hunter Biden insisted that he would refrain from working for foreign-owned companies if his father became president and abide by any other ethics rules that a Biden administration imposed.

In a statement to NBC News, a spokesman for the Joe Biden campaign didn’t address Hunter Biden’s overseas dealings but he portrayed Trump’s attacks as an act of desperation.

"Donald Trump is terrified of facing Joe Biden,” spokesman Andrew Bates, said.

“Behind closed doors, he tried to bully Ukraine into lying about the vice president. After being caught, he then publicly begged Ukraine and China to bail out his sinking campaign," Bates said. "Meanwhile, the Trump Organization is feeding off the American peoples' tax dollars like a parasite, and news recently broke that Rudy Giuliani's associates have been seeking to profit off of their shady 'alternative fact'-finding trips to Ukraine.”