The Justice Department is investigating the tax affairs of President-elect Joseph R. Biden Jr.’s son Hunter, he disclosed in a statement on Wednesday.
The investigation is being led by the U.S. attorney’s office in Delaware. It was opened in late 2018 and has included inquiries into potential criminal violations of tax and money laundering laws, according to people familiar with the inquiry. The money laundering aspect of the case failed to gain traction after F.B.I. agents were unable to gather enough evidence for a prosecution, the people said.
“I learned yesterday for the first time that the U.S. attorney’s office in Delaware advised my legal counsel, also yesterday, that they are investigating my tax affairs,” Hunter Biden said in a statement. “I take this matter very seriously, but I am confident that a professional and objective review of these matters will demonstrate that I handled my affairs legally and appropriately, including with the benefit of professional tax advisers.”
The inquiry was focused on Hunter Biden and some of his associates, not the president-elect or other family members, two people familiar with it said. On Tuesday, prosecutors in Delaware served subpoenas, including at least one that sought information related to Hunter Biden’s taxes, two people familiar with the matter said.
The disclosure of the federal investigation seems certain to exacerbate the politically tense relationship between the departing Trump White House and the incoming Biden administration. The timing means it is possible that one of the last decisions of the Trump Justice Department could be about a potential case against the son of the incoming president, if investigators uncover enough evidence to go forward.
It also means that Mr. Biden will most likely come into office as the Justice Department is actively investigating his son, a case his political opponents are certain to seize on to try to damage the early days of his presidency.
The investigation could also complicate Mr. Biden’s efforts to instill public confidence that the department can operate independent of the personal interests of the president after it became deeply politicized under President Trump. Last week, Mr. Biden said that establishing separation between the department and the White House was a top priority.
“I’m not going to be telling them what they have to do and don’t have to do. I’m not going to be saying go prosecute A, B or C,” Mr. Biden said in an interview with CNN. “It’s not my Justice Department. It’s the people’s Justice Department.”
Spokeswomen for the Justice Department and the U.S. attorney’s office in Delaware declined to comment on the investigation. Hunter Biden’s lawyer did not respond to messages seeking comment.
The tax issues came to the attention of F.B.I. agents after they opened the money laundering investigation into Hunter Biden’s financial affairs in late 2018, under the attorney general at the time, Jeff Sessions, according to several people familiar with the inquiry.
What prompted the F.B.I. inquiry remains unclear. Former law enforcement officials said that though the money-laundering aspect of the inquiry appears to have died out, investigators with the Internal Revenue Service continued to examine Mr. Biden’s taxes.
By early 2017, Mr. Biden and his first wife, Kathleen, who were then estranged, owed $313,970 in taxes, and had “maxed-out credit-card debt” and “double mortgages on both real properties they own,” according to a filing she submitted in their divorce.
The next year, the I.R.S. issued a lien against the pair, who were by then divorced, for $112,805 in unpaid taxes from 2015. Those taxes appear to have been paid off by March of this year, when the lien was released.
Separately, the city government of Washington, D.C., where Mr. Biden had lived, issued liens against him in July totaling nearly $454,000 for unpaid taxes from 2017 and 2018. Those liens were released less than one week later, according to tax records.
Mr. Biden has long been an intense target of Mr. Trump and his allies over the range of business ventures he pursued around the world during his father’s time as vice president and beyond.
He was paid $50,000 a month or more to serve on the board of Burisma, a Ukrainian energy company owned by an oligarch who was widely seen as corrupt, advised a wealthy Romanian business executive facing corruption charges and invested in a private equity fund linked to the Chinese government.
Mr. Trump’s impeachment centered on allegations that he abused his powers over American foreign policy in part to damage the Biden campaign by pressuring the government of Ukraine to announce an investigation into Hunter Biden’s dealings there. The Republican-led Senate acquitted the president in February.
Mr. Biden and a group of partners — including his uncle James Biden, the president-elect’s brother — were also involved in negotiations about a joint venture with a Chinese energy and finance company called CEFC China Energy in 2017, documents provided by a jilted former business partner show.
While the deal appears to have fizzled, an investigation by Republican-controlled Senate committees found that a subsidiary of CEFC transferred $100,000 in August 2017 to a law firm controlled by Hunter Biden. The transaction was flagged as suspicious, according to the report produced by the Republican investigation, which cited an unspecified “confidential document.” A Senate aide said it was a U.S. government record but would not describe it further.
The Republican report, which was released weeks before Election Day in an apparent effort to damage the Biden campaign, found no evidence of improper influence or wrongdoing by the former vice president.
Efforts by Mr. Trump and his supporters to damage Mr. Biden’s presidential campaign took on new urgency in October after The New York Post published reports based on files from a laptop that appeared to have belonged to Hunter Biden. The Post, which obtained materials from Mr. Trump’s personal lawyer Rudolph W. Giuliani, reported that the laptop had been seized by the F.B.I.
“We’ve got to get the attorney general to act,” Mr. Trump said in an interview on “Fox & Friends” after the Post article was published. “He’s got to act fast. He’s got to appoint somebody. This is major corruption, and this has to be known about before the election.”
A Republican congressman, Representative Ken Buck of Colorado, called on the Justice Department on Wednesday to appoint a special counsel. “This needs to be investigated free from political interference,” he said on Twitter. “No matter who is in the White House.”
The Biden team has rejected some of the claims made in the Post articles, but has not disputed the authenticity of the files upon which they were based.
A computer repair shop owner in Wilmington, Del., named John Paul Mac Isaac has said Hunter Biden left a damaged Apple computer at his store in April 2019 and asked him to recover any data. Mr. Isaac said that Mr. Biden filled out a work order and identified himself as Hunter Biden, and that he came to his shop twice but never returned to retrieve the computer or an external hard drive on which its contents had been stored.
As part of the F.B.I.’s closely held money-laundering investigation into Mr. Biden, agents working with federal prosecutors in Delaware authorized a federal grand jury subpoena and obtained the laptop and an external hard drive. People familiar with the examination said that the F.B.I. examined the laptop but that its contents did not advance the money-laundering investigation.
Before giving it to the F.B.I., Mr. Isaac said in an interview in October, he copied the contents of the external hard drive, which were later provided to Mr. Giuliani, who claimed the laptop showed evidence of corruption by Mr. Biden.
Mr. Trump and his allies openly pressed the Justice Department to disclose negative information about Mr. Biden ahead of the election, but investigators did not make overt moves that would have exposed the investigation before the ballots were cast.