Charges against President Trump's former national security adviser Michael Flynn should have never been brought, Ken Starr said Saturday.

Appearing on "Fox & Friends Weekend," Starr argued that the circumstances surrounding Flynn's eventual 2017 guilty plea and the events that followed were a "terrible injustice."

Flynn, a retired general, was charged with lying to the FBI about his conversations with Russian Ambassador Sergey Kislyak before Trump's inauguration.

Starr, the former Whitewater independent counsel, also blasted the recent appointment of Judge John Gleeson as a "friend of the court" by U.S. District Judge Emmet Sullivan, who took the plea.

ANDY MCCARTHY: MISSING FLYNN 302 CASE REPORT COULD HAVE 'MANY ITERATIONS,' NOT NECESSARILY REPRESENTATIVE OF FLYNN'S STATEMENTS

Sullivan's move came after the Justice Department filed a motion to dismiss Flynn's case entirely.

Starr believes the federal judge's decision is illegal.

"In our system of government, the decision whether to prosecute and to drop a prosecution is entirely vested in the Justice Department. And, ultimately, in the attorney general. So it's inappropriate. I think it's unlawful. And it’s unlawful by the way under the law of the D.C. Circuit in which Judge Sullivan sits," he argued.

Starr said the proof is in the details.

FILE - In this Feb. 10, 2020, file photo, Attorney General William Barr speaks at the National Sheriffs' Association Winter Legislative and Technology Conference in Washington. (AP Photo/Susan Walsh, File)

FILE - In this Feb. 10, 2020, file photo, Attorney General William Barr speaks at the National Sheriffs' Association Winter Legislative and Technology Conference in Washington. (AP Photo/Susan Walsh, File)

"When serious questions were raised about the legitimacy and the lawfulness of Gen. Flynn's prosecution by the Bob Mueller team, [Attorney General Bill Barr] appointed a very respected United States attorney from St. Louis ... to take a fresh look ... at all the new evidence that's come in. Evidence that apparently had been withheld from Gen. Flynn's defense lawyers," Starr said.

U.S. Attorney Jeffrey Jensen's investigation apparently led to the motion to clear Flynn.

"The prosecution never should have been brought in the first instance," Starr said.

"The attorney general accepted that it’s his responsibility and, with all due respect to ... Sullivan, he is overstepping his bounds here," Starr said.  "And Judge Gleeson was right eight years ago in saying it would be an abuse of discretion for him not to accept the plea that had been entered into or to dismiss the charges that had been previously brought."

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Starr argued that even if Flynn made a false statement to the FBI, the information was not  "material or relevant to the prosecution."

"So the charges never should have been brought and this been a terrible injustice to Gen. Flynn," he said.