Former Special Counsel Robert Mueller has spoken in defence of Roger Stone's conviction, saying that he "remains a convicted felon".
"Stone was prosecuted and convicted because he committed federal crimes. He remains a convicted felon, and rightly so", Mueller said in an op-ed published in The Washington Post on Saturday.
Mueller went on to defend the Russia investigation conducted during his tenure in the office, saying that it was "of paramount importance" and he was "compelled to respond both to broad claims that our investigation was illegitimate and our motives were improper".
Mueller's op-ed came after White House Press Secretary Kayleigh McEnany dismissed Mueller and his team's investigation as a "witch hunt" against President Donald Trump.
"As it became clear that these witch hunts would never bear fruit, the Special Counsel's Office resorted to process-based charges leveled at high-profile people in an attempt to manufacture the false impression of criminality lurking below the surface", she said.
On Friday, President Trump signed an executive order commuting Stone's sentence. Stone is one of the six Trump associates who were convicted following Mueller's investigation into an alleged conspiracy between the US president and Russia during the 2016 election campaign, the so-called "Russiagate".
Stone and was sentenced to 40 months in jail, but the White House argues that he had no charges for any collusion-related crime; he was convicted for his conduct during the probe.
Allegations of US-Russia collusion prompted an almost two-year probe into the matter. However, the final report of Mueller stated no evidence of collusion was found between President Trump and Russia during the 2016 presidential campaign.
Russian officials have repeatedly refuted the accusations, saying Moscow has never meddled in the US' internal affairs.
McEnany explained on Friday that because no evidence of conspiracy was found, Mueller's team could not charge Stone for that type of crime. "Instead, they charged him for his conduct during their investigation", she said.
"The simple fact is that if the Special Counsel had not been pursuing an absolutely baseless investigation, Mr. Stone would not be facing time in prison", McEnany concluded.
In his op-ed, Mueller reiterates what his 2019 report concluded - no evidence of collusion with Russia, but claims that the investigation "did establish" that Russia sought to secure a Trump presidency and that Trump's campaign expected it would "benefit electorally from information stolen and released through Russian efforts".
Stone served as a liaison between the Trump campaign and the online platform WikiLeaks, which published stolen emails of internal discussions within Democratic candidate Hillary Clinton's campaign.