US President Donald Trump’s convicted former national security adviser Michael Flynn will appear in court on Monday for the first time since hiring a new lawyer who criticized Special Counsel Robert Mueller’s investigation into Russian interference in the 2016 election. The lawyer, Sidney Powell, is a conservative commentator who frequently appears on Fox News and sells t-shirts that say “Creeps on a Mission” featuring images of Mueller, former FBI Director James Comey and other Justice Department officials. Flynn was among the first people in Trump’s inner circle to be charged by Mueller’s prosecutors for lying to investigators about his December 2016 conversations with Sergei Kislyak, Russia’s then-ambassador in Washington, about US sanctions imposed on Moscow by President Barack Obama. Flynn worked on Trump’s election campaign and the conversations took place between Trump’s November election victory and his inauguration in January 2017. Flynn pleaded guilty to the charge, agreed to cooperate with Mueller’s investigation and has also assisted prosecutors in a separate federal case brought against his former business partner, Bijan Rafiekian. Rafiekian is scheduled to go on trial in July after being indicted on allegations of unregistered lobbying on behalf of Turkey. Rafiekian denies the charge. Flynn was supposed to be sentenced in December but his sentencing was postponed after a contentious hearing in which US District Court Judge Emmet Sullivan excoriated Flynn for lying to investigators, and accused the retired US Army lieutenant general of selling out the United States. “I’m not hiding my disgust, my disdain for this criminal offense,” Sullivan said at the time. Sullivan then gave Flynn the option to have his sentencing delayed so that he could fully cooperate with any pending investigations to help bolster his case for leniency. It is unclear whether Flynn may change his legal strategy before his sentencing. His previous lawyers were Robert Kelner and Stephen Anthony. Powell has written opinion pieces in which she called for Flynn to consider withdrawing his guilty plea. However, after Flynn hired her she said in a statement that Flynn would “continue to cooperate with the government in all matters.” Prosecutors and Powell said that Flynn could still be called as a witness in Rafiekian’s trial, according to a joint status report in US District Court for the District of Columbia on June 14. But apart from that, they said, Flynn’s “cooperation is complete.” Both sides have asked the judge if they could file another status report in 60 days to give Powell more time to prepare for Flynn’s sentencing hearing.