Barr first confirmed publicly before Congress on April 9 that he was launching a separate investigation from the ongoing Justice Department inspector general probe into whether there was any improper or unauthorized surveillance of members of the Trump campaign prior to Trump's inauguration.
"I didn't understand his answer because I certainly thought the attorney general answered it perfectly", Trump told reporters Tuesday. Barr is working in close collaboration with CIA Director Gina Haspel, Director of National Intelligence Dan Coats and FBI Director Christopher Wray, the source said.
"You know what? I am so proud of our attorney general that he is looking into it".
"I believe that the Federal Bureau of Investigation is engaged in investigative activity, and part of investigative activity includes surveillance", Wray said.
Despite being a Trump appointee, Durham was recommended for the position by Connecticut's Democratic senators Richard Blumenthal and Chris Murphy who characterized him as having earned "immense respect as a no-nonsense, fierce and fair prosecutor".
"Yes, I think spying did occur", Barr repeated, adding, "but the question is whether it was predicated, adequately predicated".
Thomas Carson, a spokesman for Mr. Durham's office, declined to comment, as did a spokeswoman for the Justice Department.
Mr. Durham, who was nominated by Mr. Trump in 2017 and has been a Justice Department lawyer since 1982, has conducted special investigations under administrations of both parties.More news: Kim Kardashian to welcome fourth child as surrogate goes into labour
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Durham is a career federal prosecutor who has handled high-profile investigations before, including a probe into the destruction of Central Intelligence Agency tapes in 2005 of detainees being interrogated.
To maintain Bulger's "cover" Robert Mueller, then with the FBI, allowed four men - later declared innocent by a federal judge - to remain in prison, two until their deaths.
His use of the term "spying" to describe court-authorized surveillance aimed at understanding a foreign government's interference in the election touched off criticism that he was echoing politically charged accusations by Mr. Trump and his Republican allies that the F.B.I. unfairly targeted the Trump campaign.
The investigation is examining intelligence and surveillance used during the Russian Federation investigation that shadowed Donald Trump's presidency for almost two years.
Last month, Barr said that he believed "spying did occur" on the Trump campaign three years ago, though he's offered no details about what "spying" may have taken place.
Some Republicans, however, wanted the Justice Department to appoint a special counsel, who would have broader powers and more independence, to investigate the origins of the Russian Federation probe.
Democrats have accused Trump of using the allegations to divert attention from the special counsel Robert Mueller's findings that Russian Federation aided Trump's 2016 campaign and that he could not exonerate the president on the question of whether he tried to impede Mueller's investigation.