Hunter Biden is urging an investigation into those he accuses of trafficking in stolen material from his laptop.
In letters filed on Wednesday, lawyers representing the US president’s son named a computer repair shop owner and Rudy Giuliani as among those who they say had broken the law.
Hunter also threatened to sue Fox News’ Tucker Carlson for defamation.
It’s a shift in strategy for him to hit back after years of scrutiny, a source close to him told CBS News.
The laptop’s existence was first brought to the public’s attention by the New York Post less than one month before the 2020 presidential election.
It had allegedly been left by Hunter Biden in a repair shop and never collected.
The Post alleged that emails found on the computer’s hard-drive suggested Hunter’s business dealings abroad were influencing US foreign policy while his father was vice-president.
Former US president Donald Trump seized on the laptop as a campaign issue, saying it was evidence of corruption.
Hunter Biden, 52, is a lawyer and lobbyist who has worked abroad including in China and Ukraine.
The FBI has been investigating his business dealings since 2018 and has gathered enough evidence to charge him with tax crimes, and CBS News claim that they appear to have gathered enough evidence suggesting tax crimes may have been committed.
And Republicans have vowed to investigate him and the family business now they have control of the House of Representatives.
“We have evidence – that we’ve been transparent with and will continue to be transparent with – where this family has taken in millions and millions of dollars from our adversaries, mainly in China,” said the chairman of the oversight committee, James Comer.
The president and his family have denied any wrongdoing in overseas business dealings.
In the latest development, Hunter’s lawyers wrote letters to the Justice Department, the attorney general of Delaware and the Internal Revenue Service.
They asked them to investigate former computer repair shop owner John Paul Mac Isaac, former Trump advisers Rudy Giuliani and Steve Bannon and their lawyer, Robert Costello.
Lawyers said they believed various Delaware laws were breached “in accessing, copying, manipulating, and/or disseminating Mr Biden’s personal computer data”.
But Abbe Lowell, an attorney for Hunter Biden, said in a statement to CBS News that the letters “do not confirm Mac Isaac’s or others’ versions of a so-called laptop.”
In response to Hunter Biden’s new suite of legal threats, a lawyer for Mr Isaac said “the only thing I see is a privileged person hiring yet another high-priced attorney to redirect attention away from his own unlawful actions”.
Mr Isaac also claims that the laptop was left with him for repair in April 2019, and Hunter Biden never returned to collect it.
He said he reviewed the laptop files shortly after receiving it and discovered information about Mr Biden’s personal finances. After waiting 90 days – the amount of time that had to pass before something could be considered abandoned property – Mr Isaac considered it abandoned.
He turned the laptop over to the FBI and provided a copy of the contents to Mr Guiliani, who later would pass it along to the New York Post.
Mr Costello, a lawyer for both Mr Giuliani and Steve Bannon, told CBS News the letters to the Justice Department and Delaware were a “frivolous legal complaint trying to intimidate”.
