Hunter Biden had a tax lien filed against him for more than $112,000 in unpaid income taxes in 2015—his first full year serving on the board directors of Burisma Holdings, a Ukrainian natural gas conglomerate.

The Internal Revenue Service (IRS) filed the lien against Hunter Biden, the youngest son of former Vice President Joe Biden, and his wife after failing to receive payment for their tax liability on income earned in 2015, according to documents obtained by the Daily Caller. The lien is still active as no release documents have been filed by the IRS.

“We have made a demand for payment of this liability, but it remains unpaid,” the IRS wrote in a notice to the recorder of deeds of Washington, DC, in November 2018. “Therefore, there is a lien in favor of the United States on all property and rights to property belonging to this taxpayer for the amount of these taxes.”

The lien was issued on income garnered during Hunter Biden’s first year on Burisma’s board of directors, where he was paid as much as $83,000 per month. The role, itself, has drawn significant scrutiny in recent weeks, especially after President Donald Trump suggested the Ukrainian government look into how and why Hunter Biden was able to secure the position, despite no background in the energy sector.

Congressional Democrats argued that action amounted to asking a foreign government for dirt on a domestic political opponent when voting to impeach the president earlier this month.

Trump and his allies, on the other hand, have claimed Hunter Biden’s appointment, coming around the same time his father was tapped to lead Obama-era policy towards Ukraine, and his relative inexperience in the energy industry, warrant investigation.

As Peter Schweizer detailed in Secret Empires: How the American Political Class Hides Corruption and Enriches Family and Friends, Hunter Biden’s background in banking, lobbying, and hedge fund management paled in comparison to that of current and past members of Burisma’s board.

Adding to concerns was that Hunter Biden joined the company at a time when it was actively courting western leaders to prevent scrutiny of its practices. The same month as the appointment, Mykola Zlochevsky, Burisma’s founder, had his assets frozen in the United Kingdom on suspicion of money laundering. A Ukrainian official with ties to Zlochevsky admitted in October the only reason Hunter Biden secured his position with Burisma was to “protect” the company from foreign scrutiny.

It is in the context of Burisma and Zlochevsky’s legal troubles that Joe Biden’s political influence has raised the most red flags. The former vice president has particularly drawn questions over his conduct in demanding the Ukrainian government fire its top prosecutor, Viktor Shokin, in 2016. Joe Biden, who has publicly bragged about the firing, reportedly threatened to withhold more than $1 billion in U.S. aid if the Ukrainian government did not remove Shokin. He has claimed the demand came from then-President Barack Obama, who had allegedly lost faith in the prosecutor’s ability to tackle corruption.

Unofficially, though, it was known that Shokin was investigating both Burisma and Zlochevsky for public corruption. It is uncertain if the probe extended to Hunter Biden, although Shokin has recently admitted that prior to his ouster, he was warned to back off the matter. Regardless of what occurred, Shokin’s successor, who is now himself being investigated for public corruption, dropped the investigation into Burisma.

After the investigation into Burisma was closed, Hunter Biden remained on the company’s board of directors until his term expired in April 2019. During his tenure, Burisma wired millions of dollars to a Morgan Stanley bank account controlled by the younger Biden and his business associates. Between November 2014 and November 2015 alone, Burisma transferred more than $3.5 million to the account.

Of that sum, $1.2 million went into an escrow account in Los Angeles, California, where Hunter Biden currently resides and his law firm is registered.