In the wake of the Ukraine scandal and the impeachment proceedings it sparked, Donald Trump and his camp are focusing on turning attention to Democratic presidential frontrunner Joe Biden and his son, Hunter. During Trump’s controversial call with Ukrainian President Volodymyr Zelensky, he pressured Zelensky to dig up dirt on Biden. Now, Trump claims that Biden intervened with Ukraine’s legal system to fire Ukraine’s top prosecutor, Viktor Shokinor, who was investigating corruption in the for-profit energy company, Burisma, that employed Hunter.

Yet critics of the theory suggest that it has long been debunked, Newsweek reports. One such critic is Fox News senior judicial analyst Andrew Napolitano, who said on Fox & Friends on Tuesday that prosecutors in both Ukraine and the United States dismissed the allegations.

“If you talk to [Trump’s personal lawyer] Rudy Giuliani, he’s got a lot of evidence of inappropriate behavior by the former vice president [Biden] and his son. Yet the prosecutors in Ukraine and even prosecutors here in the United States say there’s no there there,” the former New Jersey Superior Court judge pointed out.”