"I take this matter very seriously, but I am confident that a professional and objective review of these matters will show that I have handled my affairs legally and appropriately, including with the benefit of professional accountants," said Hunter Biden.
Hunter Biden, an attorney whose late brother Beau Biden was the Delaware Attorney General before his death, did not reveal any further details of the investigation.
Kim Reeves, a spokeswoman for David Weiss, the US attorney for Delaware, said in an email: "According to DOJ [Department of Justice] guidelines, we cannot comment on an ongoing investigation."
CNN reported later Wednesday that it had reached out to Hunter Biden's attorney and his father's presidential campaign last week for comment on the investigation. CNN reported that "several financial issues are being investigated, including whether Hunter Biden and employees have broken tax and money laundering laws in doing business in foreign countries, primarily China."
CNN reported that the investigation has been "largely dormant for the past few months" as the Justice Department has enacted regulations prohibiting legal action in cases that could affect an election.
Publicly available documents show Hunter and his ex-wife Kathleen Buhle had a lien on unpaid taxes, possibly including interest and penalties, totaling $ 112,805.09 as of March last, NBC News reported. The documents submitted by the IRS show that the lien was issued in November 2019. It is not immediately clear whether the lien has anything to do with the investigation.
The New York Post reported in October that in December 2019 the FBI seized both a computer and hard drive believed to belong to Hunter Biden after the owner of a computer repair facility in Wilmington, Delaware, told federal authorities that that he was in possession of these items.
The shopkeeper gave a copy of the hard drive to an attorney for Rudy Giuliani, President Donald Trump's personal attorney, the Post reported. Giuliani then gave the newspaper a copy of the hard drive.
In a statement on Wednesday, the transition team of Democrat Joe Biden and Vice President-elect Kamala Harris said: "President-elect Biden is deeply rejuvenated of his son who has only struggled through difficult challenges, including the vicious personal attacks of recent months step forward. "
The White House and the US Department of Justice, which oversees US law firms, declined to comment.
Hunter Biden has long struggled with drug addiction and other personal problems.
He was despised in court earlier this year for failing to provide financial information to an Arkansas woman who said she gave birth to his child.
That woman's attorneys, Lunden Alexis Roberts, said in January that Hunter Biden failed to meet a court-ordered deadline for submitting documents five years ago as part of her application for child support for her then 16-month-old wife Child.
These documents included "a list of all sources of income", copies of tax returns and a list of companies in which he is involved, court records showed.
Hunter Biden, who originally claimed he never had sex with Roberts, later quit denying that he was the child's father.
He closed the case with Roberts in March by agreeing to pay her an undisclosed amount each month for child support and agreeing to maintain health insurance for the child. He also agreed to pay Roberts an undisclosed amount of money, which apparently included her attorney's fees and expenses.
During the presidential election, Republican Trump and his allies made Hunter Biden a focus of political attack, particularly related to his business dealings in Ukraine and China.
Hunter Biden and his father have denied any wrongdoing related to their overseas business in which Joe Biden was not a part.
Trump, who refuses to admit he lost the election, was charged by the House of Representatives last year for withholding military aid to Ukraine appropriated by Congress when he pressured that nation's new president to investigate the Biden. Trump was acquitted after a trial by the Senate.
In an interview last week, Joe Biden told CNN that once he took office, he would not try to influence decisions by the Justice Department.
"It's not my Justice Department. It's the People's Justice Department," Biden said.
He also said the department "can independently decide who will and who will not be prosecuted".
The investigation into Hunter Biden comes after Trump's firm, the Trump Organization, is under criminal investigation by Manhattan prosecutors for explaining hush payments to women who claim they have sex with Trump. The president has denied having sex with either woman, porn star Stormy Daniels and Playboy model Karen McDougal.
The DA office could also investigate possible tax crimes as well as banking and insurance fraud, as suggested by court records.
Trump is currently battling DA Cyrus Vance Jr.'s efforts to obtain eight years worth of tax returns and other financial records from the President from his longtime accountants.
At the same time, the New York attorney general's office is conducting a civil investigation for possible misstatements about the value of Trump Organization real estate. The President's son, Eric Trump, was recently questioned by investigators from the AG's office as part of this investigation.
Trump's daughter Ivanka Trump, a senior White House adviser, was dismissed last week on a lawsuit by the Washington, DC Attorney General's office. This AG accuses the Trump Organization, the Trump Opening Committee and the Trump International Hotel in this city of "openly and unlawfully misused charitable funds to enrich the Trump family" in connection with the expenditures for the inauguration of Trump 2017.
According to research by The New Yorker, ProPublica, and WNYC, Ivanka Trump and her other adult brother, Donald Trump Jr., narrowly avoided criminal charges by Vance's office in connection with the marketing of the Trump SoHo Hotel in New York in 2012. Vance's office had looked into whether potential buyers had been misled about the project's success.
The outlets reported that Marc Kasowitz, an attorney for Ivanka and Donald Jr., donated $ 25,000 to Vance's re-election campaign and appealed directly to him to drop the case.
– Additional coverage from Mike Calia, Tucker Higgins, and NBC News