Mueller expressed concerns with Barr's conclusions

In a letter addressed to Attorney General William Barr, Special Counsel Robert Mueller expressed his concerns regarding the justice official's conclusions of the 22-month-long investigation into Russian collusion in the 2016 Presidential elections.

Mueller allegedly told Barr that the Attorney-General's four-page letter to the US Congress containing the takeaways did not fully capture his 448-page report, as per CNN.The two also spoke by phone, where Mueller put forth his concerns. The Special Counsel told Barr that his letter was more nuanced when it came to the obstruction of justice charges against US President Donald Trump.

Even though Mueller gave a clean chit to Trump when it came to Russian collusion in his Presidential campaign, the Special Counsel fell short of completely exonerating the incumbent President when it came of obstruction of justice charges.

The Attorney-general, however, chose not to pursue a case against Trump, citing a lack of sufficient evidence in Mueller's report. This move has been highly criticised by Democratic party leaders, who have demanded the complete release of Mueller's report even though a redacted version of it exists in the public domain.

"The Special Counsel's decision to describe the facts of his obstruction investigation without reaching any legal conclusions leaves it to the Attorney General to determine whether the conduct described in the report constitutes a crime," Barr's summary had stated.

"After reviewing the Special Counsel's final report on these issues; consulting with Department officials, including the Office of Legal Counsel; and applying the principles of federal prosecution that guide our charging decisions, Deputy Attorney General Rod Rosenstein and I have concluded that the evidence developed during the Special Counsel's investigation is not sufficient to establish that the President committed an obstruction-of-justice offence," Barr wrote in his summary.

While the White House is yet to comment on the letter, Trump attorney Rudy Giuliani, referring to the obstruction questions, told CNN: "Mueller should have made a decision and shouldn't be complaining or whining now that he didn't get described correctly."

On the other hand, Justice Department spokesperson Kerri Kupec in a statement issued on Tuesday highlighted that Mueller did not tell Barr that anything in the letter was factually wrong.

Barr is due to testify before the Senate Judiciary Committee on Wednesday in relation to the Mueller report.