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 crackdown on corruption.

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.

Read the full story on NBC's website.