Lowell argued in the letters that Mac Isaac and the others had no right to inspect the contents of Biden's laptop, much less make copies of it to share with the media.
"This failed dirty political trick directly resulted in the exposure, exploitation, and manipulation of Mr. Biden’s private and personal information," Lowell wrote in a letter. "Politicians and the news media have used this unlawfully accessed, copied, distributed, and manipulated data to distort the truth and cause harm to Mr. Biden."
The DOJ did not immediately respond to a request for comment from Fox News Digital.
COMER SOUNDS ALARM ON BIDEN'S MISHANDLING OF CLASSIFIED DOCUMENTS: ‘NOTHING’ HE'S DONE IS ‘NORMAL’
Hunter Biden's lawyers are going on offense against his critics. (Getty Images)
Hunter Biden's lawyers sent letters demanding a criminal investigation of Rudy Giuliani. (Spencer Platt/Getty Images)
The letter went on to accuse Mac Isaac of "theft of computer services," and Giuliani of "possession of stolen property.
"Mr. Mac Isaac chose to work with President Donald Trump’s personal lawyer to weaponize Mr. Biden’s personal computer data against his father, Joseph R. Biden, by unlawfully causing the provision of Mr. Biden’s personal data to the New York Post," Lowell wrote.
Despite the appearances, a source familiar with Lowell's move argued that Wednesday's letters do not constitute an admission of the laptop's validity. Biden's legal team argues that the versions of the laptop released to the public may have been tampered with.
Hunter Biden's legal team is demanding a criminal investigation into Steve Bannon. (AP Photo/Jose Luis Magana)
The First Son's newfound legal aggression comes as Republicans on Capitol Hill are preparing their own investigations into both him and President Biden's family more generally.
An upcoming hearing for the House Oversight Committee will focus on Twitter's censorship of the New York Post's original story on the so-called "laptop from hell," which dropped just weeks before Election Day in 2020.
Other House investigations are expected to focus on Hunter's business dealings. Those investigations are likely to rely heavily on the contents of the laptop.
The Associated Press contributed to this report.