A United States judge on Monday flatly rejected a last-ditch effort by President Donald Trump‘s former national security adviser Michael Flynn to get criminal charges against him to which he already has pleaded guilty dropped, brushing aside his claims of misconduct by prosecutors and the FBI.

US District Judge Emmet Sullivan ordered Flynn to appear for sentencing on January 28, concluding that Flynn had failed to prove a “single” violation by the prosecution of withholding evidence that could exonerate him.

The 92-page ruling by Sullivan represented a major blow to Flynn, who has tried to backpedal since he pleaded guilty in 2017 to lying to the FBI about his conversations with then-Russian Ambassador Sergey Kislyak.

Flynn was one of several former Trump aides to plead guilty or be convicted at trial in then-special counsel Robert Mueller‘s investigation that detailed Moscow’s interference in the 2016 US election to boost Trump’s candidacy as well as numerous contacts between Trump’s campaign and Russia.

Flynn was previously supposed to have been sentenced by Sullivan in December 2018, but sentencing was delayed. The judge also has excoriated Flynn for lying to the FBI and accused him of selling out his country.

Since that time, Flynn dismissed his former lawyers on the case and tapped Sidney Powell, a frequent Fox News guest who has often expressed hostility toward the FBI and Mueller.

In a series of requests, Powell asked the court to force the Justice Department to turn over troves of records that she said would show the FBI conducted an “ambush” interview of Flynn and withheld evidence that could exonerate him.

“The court summarily disposes of Mr Flynn’s arguments that the FBI conducted an ambush interview for the purpose of trapping him into making false statements and that the government pressured him to enter a guilty plea,” Sullivan wrote in the ruling. “The record proves otherwise.”