The incoming chairman of the Senate Judiciary Committee said Wednesday that Attorney General nominee William Barr has confidence in special counsel Robert Mueller and will let him complete his Russia investigation.

South Carolina Republican Sen. Lindsey Graham said after meeting with Barr, who led the Justice Department under President George H.W. Bush, that Barr has a 'high opinion' of Mueller. Barr was spending most of Wednesday on Capitol Hill, meeting senators on the committee before his confirmation hearing next week.

'He had absolutely no indication he was going to tell Bob Mueller what to do or how to do it,' Graham said.

Graham said Barr told him about his longtime relationship with Mueller. Barr and Mueller worked together when Barr was Bush's attorney general between 1991 and 1993 and Mueller oversaw the department's criminal division. Graham said the two men were 'best friends' and have known each other for 20 years.

Their wives attend Bible study together, Graham explained, and Mueller attended the weddings of two of Barr's daughters.

President Donald Trump's attorney general nominee, William Barr, told Trump confidant Sen. Lindsey Graham that he doesn't believe Special Counsel Robert Mueller is running what President Trump calls a 'witch hunt' and has no plan to fire him if he takes over the Justice Department

Mueller (pictured) is Barr's 'best friend,' according to Graham, who said the two men have known each other for 20 years and their wives attend a Bible study together

Graham listed a number of questions that he had put to Barr: 'I asked Mr. Barr directly, 'Do you think Mr. Mueller is on a witch hunt?' He said no. 'Do you think he would be fair to the president and the country as a whole?' He said yes. 'And do you see any reason for Mr. Mueller's investigation to be stopped?' He said no. 'Do you see any reason for a termination based on cause?' He said no. 'Are you committed to making sure Mr. Mueller can finish his job?' Yes.'

Graham said Barr said that if he were attorney general, he would 'err on the side of transparency' when he eventually received Mueller's report.

President Donald Trump pushed out Attorney General Jeff Sessions in November and made Sessions' chief of staff Matthew Whitaker the acting attorney general before nominating Barr in December.

Trump's critics have expressed concern that Barr may try to curtail Mueller's investigation, which Trump repeatedly has called a 'hoax' and a 'witch hunt.' Also, Barr wrote an unsolicited memo to the Justice Department last year critiquing Mueller's investigation into whether the president had sought to obstruct justice by firing James Comey as FBI director.

'So his opinion of Mr. Mueller is very, very high in terms of ethics and character and professionalism,' Graham said.

Barr sat own with Graham (right) and other Republican senators on Wednesday in advance of whta will be a contentious confirmation hearing next week on Capitol Hill

Senate Minority Leader Chuck Schumer said Wednesday in a floor speech that Trump should withdraw Barr's nomination to replace former Attorney General Jeff Sessions, citing his past complaints about Mueller's Russia probe

Trump fired Sessions last year and replaced him with then-Justice Department Chief of Staff Matt Whitaker on an interim basis

Senate Minority Leader Chuck Schumer painted a different picture in remarks on the Senate floor, citing a memo Barr wrote to Deputy Attorney General Rod Rosenstein last year.

In that memo, he criticized Mueller’s Russia probe – writing that his investigation into possible obstruction of justice related to Trump's firing of FBI Director James Comey was 'fatally misconceived.'

Barr also wrote then that Mueller should not be permitted to 'demand' in-person question of the president.

The Senate 'should subject Mr. Barr’s views to the strictest of scrutiny next week and I still believe, after the revelations about Mr. Barr’s unsolicited memo, President Trump ought to withdraw this nomination,” Schumer said.

Barr was attorney general during the George H.W. Bush presidency, and is poised to return to the Cabinet job again

Graham said Barr told him that he has a high opinion of Rod Rosenstein, the current deputy attorney general who has so far overseen the Mueller investigation and is expected to leave office if Barr is confirmed.

'Mr. Rosenstein mentioned to him when they first met, I think, that two years would probably be enough' Graham said. 'He has got some ideas of a deputy. I told him to pick somebody you are comfortable with and that the president can approve, and I trust his judgment to find a worthy successor to Mr. Rosenstein.'

Barr also met with the outgoing committee chairman, Republican Sen. Chuck Grassley of Iowa, who said he believes Barr's previous experience 'ought to make his nomination very easy.'

Barr's other scheduled meetings on Wednesday included sit-downs with Republican Sens. John Cornyn of Texas and Ben Sasse of Nebraska.