Michael Flynn, former U.S. national security adviser, exits federal court in Washington, D.C., on Monday, June 24, 2019.

A federal judge on Tuesday tentatively set Dec. 18 for the criminal sentencing of Michael Flynn, President Donald Trump's first national security advisor.

That date is exactly one year after Flynn's first sentencing, which was aborted in U.S. District Court in Washington, D.C., by Judge Emmet Sullivan to give Flynn additional time to complete his agreed-to cooperation with then-special counsel Robert Mueller's investigation.

During that hearing, Sullivan had blasted Flynn, saying "arguably you sold your country out," and warned him he might sent Flynn to jail if he did not agree to postpone his sentencing.

Flynn, a retired Army lieutenant general, pleaded guilty in October 2017 to lying to FBI agents about his contact with then-Russian Ambassador Sergey Kislyak in the weeks leading up to Trump's inauguration.

Flynn's cooperation with federal prosecutors appears to be finished.

Also at Tuesday's hearing, Flynn's defense lawyer, Sidney Powell, told Sullivan that Flynn probably will not try to withdraw his guilty plea — but also told the judge that there had been "egregious" misconduct by prosecutors.

Powell said prosecutors have suppressed so-called Brady material, which is evidence that could exculpate a criminal case defendant. Powell is aiming with such arguments to have the case against Flynn dismissed.

Prosecutors, in turn, told Sullivan that they have turned over to Flynn's lawyers all material required under the Brady standard.

Meanwhile, Democratic lawmakers are demanding that Flynn submit to questioning and produce documents to them, as they pursue numerous investigations into Trump and Russian interference in the 2016 presidential election.

Last week, House Intelligence Committee Chairman Adam Schiff, D-Calif., commanded Flynn to testify before that panel on Sept. 25. Flynn had refused to comply with a subpoena issued by the Democrats in June.

Powell in a letter to the committee in late August called the subpoena "unreasonable and unethical."