WILMINGTON, Del. (NewsNation Now) — Hunter Biden, son of President-elect Joe Biden, said in a statement on Wednesday that his ‘tax affairs’ are under investigation.

According to the statement obtained by NewsNation, the investigation is being conducted by the U.S. Attorney’s office in Delaware.

“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 advisors,” Hunter Biden said in a statement.

The Justice Department’s investigation scrutinizing Hunter Biden’s taxes has been examining some of his Chinese business dealings, among other financial transactions, a person familiar with the matter told The Associated Press.

The investigation was launched in 2018, a year before his father, Joe Biden, announced his candidacy for the presidency, but it isn’t clear which entities might be tied up in the probe. Hunter Biden has a history of international affairs and business dealings in a number of countries.

Federal investigators served a round of subpoenas on Tuesday, including for Hunter Biden, according to another person familiar with the investigation who spoke on condition of anonymity to discuss an ongoing probe. The tax investigation centers on his business dealings, the person said.

Investigators did not reach out in the weeks prior to the election because of a Justice Department policy surrounding elections that prohibits overt investigative acts, one of the people said.

The Biden-Harris presidential transition team also released a statement in response to the investigation:

“President-elect Biden is deeply proud of his son, who has fought through difficult challenges, including the vicious personal attacks of recent months, only to emerge stronger.”

A New Yorker profile on Hunter Biden last year detailed some of his business work in China, including how he accompanied his father on a 2013 trip to Beijing, where he met with a business associate. He also acknowledged having received a diamond from a Chinese energy tycoon involved in liquified natural gas projects. He downplayed the idea that the gift could have been intended to affect his father’s policy. He told the magazine that he gave the diamond to an associate.

“What would they be bribing me for? My dad wasn’t in office,” he said.

Hunter Biden has been caught up in controversies before. While his father was vice president, Hunter joined the Naval Reserve and was discharged after testing positive for cocaine in his system, later revealing a yearslong struggle with addiction.

He also joined the board of Ukrainian energy company Burisma in 2014, sparking concerns about the perceptions of a conflict of interest given the elder Biden was deeply involved in U.S. policy toward Ukraine. An investigation by the Republican-led Senate did not identify any policies that were directly affected by Hunter Biden’s work.

In the weeks before the election, Trump supporters used the existence of a laptop they said was connected to Hunter Biden — and the emergence of someone who maintains he had business discussions with him — to raise questions about Joe Biden’s knowledge of his son’s activities in Ukraine and China. The president-elect has said he did not discuss his son’s international business dealings with him and has denied having ever taken money from a foreign country.

The laptop surfaced publicly in October when The New York Post reported on emails that it said had come from Hunter Biden’s laptop and that it said it received from Rudy Giuliani, Trump’s personal lawyer.

A third person familiar with the matter said the tax investigation does not have anything to do with the laptop. Like the other people who spoke to the AP, the person was not authorized to discuss the matter publicly and spoke on condition of anonymity.

This is a developing story, check back for updates.