In a sweeping rebuke of Attorney General William Barr's conclusion there was insufficient evidence in the Mueller report to show President Trump obstructed justice, over 400 former federal prosecutors have signed an open letter saying Mr. Trump would face "multiple felony charges for obstruction of justice" if he were a private citizen.

Former officials including U.S. attorneys, trial lawyers and senior members of the Department of Justice from Republican and Democratic administrations signed the letter, which was released on Medium. The letter lists several acts that "satisfy all of the elements for an obstruction charge," including Mr. Trump's efforts to fire special counsel Robert Mueller and pressure witnesses to prevent them from cooperating in the investigation.

"All of this conduct — trying to control and impede the investigation against the President by leveraging his authority over others — is similar to conduct we have seen charged against other public officials and people in powerful positions," the letter says.

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"We believe strongly that, but for the OLC [Office of Legal Counsel] memo, the overwhelming weight of professional judgment would come down in favor of prosecution for the conduct outlined in the Mueller Report," the letter says, referring to a Justice Department opinion stating a sitting president cannot be criminally prosecuted.

In his report, Mueller declined to determine whether the president's conduct amounted to obstruction of justice. As a result, in a letter to Congress describing the principal findings of Mueller's report, Barr wrote that he and his deputy, Rod Rosenstein, determined Mueller's findings were not "sufficient" to prove Mr. Trump committed a crime.

The group of former officials slammed Barr's conclusion, saying it "runs counter to logic and our experience."

"As former federal prosecutors, we recognize that prosecuting obstruction of justice cases is critical because unchecked obstruction - which allows intentional interference with criminal investigations to go unpunished - puts our whole system of justice at risk," the letter says.

Members of Congress, namely House Democrats, have since urged Mueller to testify on his findings from the report to provide greater transparency on the Russia investigation. Mr. Trump, however, said Mueller should not testify, tweeting on Sunday that there were "no redos for the Dems."