Hunter Biden could be charged with tax crimes
The FBI has gathered enough evidence to charge Hunter Biden with tax crimes and making a false statement to buy a gun, according to the BBC's US partner CBS News.
President Joe Biden's son has been under federal investigation since 2018.
The decision on whether to file criminal charges now rests with the US Attorney in Delaware.
A lawyer for Hunter said he had not been contacted by federal agents. He has repeatedly denied breaking the law.
The US Department of Justice has declined to comment.
Hunter Biden, 52, is a lawyer and lobbyist who has worked abroad including in China and Ukraine. He was discharged from the US Navy in 2014 after testing positive for cocaine.
According to the Washington Post, federal agents began investigating him in 2018, and initially centred on finances related to his overseas businesses and consulting.
Over time, the investigation began to focus on whether Hunter properly reported his income and made false statements on paperwork used to purchase a firearm in 2018.
In a book published last year he had admitted to still being a heavy user of crack cocaine at that time. But the Washington Post reports that he said "no" on a federal form asking if he was "an unlawful user of, or addicted to, marijuana or any depressant, stimulant, narcotic drug or any other controlled substance".
Criminal charges stemming from falsehoods on gun-purchase forms remain rare and number in the hundreds each year.
In a statement sent to CBS, a lawyer for the president's son said that he expected the Department of Justice to "diligently investigate and prosecute" those who leaked information about the investigation.
"As is proper and legally required, we believe the prosecutors in this case are diligently and thoroughly weighing not just evidence provided by agents, but also all the other witnesses in this case, including witnesses for the defence," the statement from lawyer Chris Clark said.
"That is the job of the prosecutors. They should not be pressured, rushed, or criticised for doing their job."
Mr Clark added that he has had no contact "whatsoever" with any federal investigators. He said any information from agents - cited by the Washington Post, which first reported the story - was "inherently biased, one-sided, and inaccurate".
Hunter Biden has long been a target of scrutiny from conservatives, who have alleged that his overseas business dealings indicate a pattern of corruption.
Republicans have vowed to investigate him in the House of Representatives if they win a majority of seats in next month's midterm congressional elections.
While the younger Biden has admitted to a troubled life and a previous "massive drug addiction", both he and President Biden have denied that he engaged in illegal activity.
He first admitted knowledge of an investigation in December 2020. In a statement at the time, Hunter Biden said he was "confident that a professional and objective review of these matters will demonstrate that I handled my affairs legally and appropriately, with the benefit of professional tax advisers".
In April, Joe Biden's chief of staff, Ron Klain, said the US president "is confident that his son didn't break the law", but that the matter would be left to the Justice Department and that the White House would not get involved.
In 2018, Hunter Biden was investigated after his then-girlfriend threw away a gun belonging to him in a rubbish bin near a school, according to US media reports.
Secret Service agents reportedly intervened, according to Politico, by visiting the Delaware store where he had bought the firearm earlier that month and requesting access to his background check form.
The gun-store owner refused to hand over the paperwork, the website reports, and no charges were filed.