Then-Democratic nominee Joe Biden argued during October's presidential debate that his son didn't make money "in terms of" China, an issue that has come under greater scrutiny as more details surfaced regarding Hunter's business deals.

"My son has not made money, in terms of this thing about ... China," Biden said at the time.

His comments came amid emails showing the younger Biden involved in setting up a business deal with a Chinese energy firm. Hunter's finances recaptured the national spotlight on Wednesday when he announced that the U.S. attorney in Delaware was investigating his tax affairs.

A source familiar with the investigation told Fox News that it involved suspicious activity reports (SARs) surrounding "China and other foreign nations." SARs are filed by financial institutions "if there is something out of the ordinary about a particular transaction," a Treasury Department official told Fox News.

BIDEN PLEDGES TO AVOID CONFLICTS OF INTEREST WITH FAMILY'S BIZ DEALINGS

While the exact details are unclear, the Biden-Harris transition team stood behind the president-elect's son.

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

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The elder Biden has repeatedly denied wrongdoing in his son's business affairs and told CNN on Thursday that he would avoid conflicts of interest after entering the White House.

"My son, my family, will not be involved in any business, any enterprise, that is in conflict with or appears to be in conflict with whether it is an appropriate distance from the presidency and government," he told CNN.