WASHINGTON >> 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 today.

The investigation was launched in 2018, a year before his father, Joe Biden, announced his candidacy for president, but it isn’t clear which entities might be tied up in the probe, and the inquiry was not disclosed to Hunter Biden until Tuesday.

The younger Biden has a history of international affairs and business dealings in a number of countries, and the revelation of a federal investigation puts a renewed spotlight on the questions about his financial dealings that dogged his father’s successful White House campaign.

Federal investigators served a round of subpoenas on Tuesday, including one 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.

In a statement released by the president-elect’s transition office, Hunter Biden said he learned about the investigation on Tuesday, but he did not disclose specifics about what was being scrutinized.

“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,” he said in a statement.

He has long been a target of President Donald Trump and his allies, who have accused him of profiting off his political connections.

Trump and his supporters also raised unsubstantiated charges of corruption related to Hunter Biden’s work in Ukraine at the time his father was vice president and leading the Obama administration’s dealings with the Eastern European nation.

The disclosure of the federal investigation, led by the U.S. attorney’s office in Delaware, comes at an awkward moment for the incoming president, who is assembling his Cabinet.

His pick for attorney general could have oversight of the investigation into the new president’s son if it is still ongoing when Biden is sworn in on Jan. 20.

The transition team said in a statement: “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.”

It could also add weight to Trump’s broad accusations that Biden was weak on China. Trump took a tough line on China during the campaign as he tried to deflect blame for the coronavirus. Biden has rejected the characterization that he was weak and said, that unlike Trump, he would rebuild global coalitions to check China’s power.

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 years-long 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.

In a CNN interview last week, President-elect Biden addressed the business dealings of his son Hunter and his brothers, pledging that they would avoid any perceived conflicts of interest during his time in office.

“My son, my family will not be involved in any business, any enterprise that is in conflict with or appears to be in conflict, where there’s appropriate distance from the presidency and government,” Biden said.