Former independent counsel Ken Starr said Monday on "The Story" that Special Counsel Robert Mueller committed an "unforgivable sin" with the leak of a letter he wrote to Attorney General William Barr.

Details of the March 24 letter went public shortly before Barr testified before the Senate Judiciary Committee in a tense hearing last week.

Multiple news outlets reported that Mueller raised concerns about how Barr's conclusions from the investigation were being portrayed, before the Justice Department had released a redacted version of Mueller's report.

Starr said he views the leak of the letter as an "unfair, whiny complaint" by Mueller, which prompted immediate calls from Democrats for him to testify at a public hearing.

Starr argued that Barr was "trying to do the right thing" by releasing a short memo to Congress summarizing Mueller's findings and he was not deserving of the ensuing criticism.

"That is, to me, the unforgivable sin. He, Bob Mueller, badly injured this attorney general and the attorney general didn't deserve that but, of course, that created its own huge firestorm including suggestions that the attorney general was totally mischaracterizing the report and so forth," Starr said.

Watch the full discussion above.

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