The former CIA director John Brennan was interviewed on Friday by US attorney John Durham’s team, as part of its inquiry into the investigation of Russian election interference in 2016. The interview took place at CIA headquarters and lasted eight hours, said Nick Shapiro, Brennan’s former deputy chief of staff and senior adviser. “Brennan was informed by Mr Durham that he is not a subject or a target of a criminal investigation and that he is only a witness to events that are under review,” Shapiro said in a statement. Brennan led the CIA as it and other agencies arrived at the conclusion that Russia interfered in the 2016 election to benefit Donald Trump. Durham is continuing to examine how US intelligence officials reached that assessment, which Trump has long resisted. Brennan appeared voluntarily and has said he welcomed the chance to be questioned and had nothing to hide. “I look forward to the day when the truth is going to come out and the individuals who have mischaracterized what has happened in the past will be shown to have deceived the American people,” Brennan told MSNBC in May. Brennan offered Durham details on efforts to “understand and disrupt” Russia’s efforts to interfere in the election, and answered questions related to a “wide range of intelligence activities” undertaken by the CIA in the run-up to November 2016, Shapiro said. Brennan also answered questions about the January 2017 intelligence community assessment that blamed Russia for the interference. A spokesman for Durham declined to comment. Attorney general William Barr last year appointed the US attorney for Connecticut to examine decisions made by officials as they investigated ties between Trump and Russia. Exhaustive reports by special counsel Robert Mueller and the Republican-led Senate intelligence committee have detailed extensive ties between Russians and Trump associates during the 2016 campaign. But Barr has challenged the idea that the FBI had sufficient basis to open its counterintelligence investigation and empowered Durham to look at other agencies too. Brennan questioned why the CIA’s findings and tradecraft were being scrutinized, given that Mueller and the bipartisan Senate report validated the conclusions on Russian interference, Shapiro said. “Brennan also told Mr Durham that the repeated efforts of Donald Trump and William Barr to politicize Mr Durham’s work have been appalling and have tarnished the independence and integrity of the Department of Justice, making it very difficult for Department of Justice professionals to carry out their responsibilities.” A spokeswoman for the justice department declined to comment. Brennan, a vocal critic of Trump, testified before Congress in 2017 that he personally warned Russia against interfering in the election and was so concerned about its contacts with Trump’s campaign he convened top officials to focus on the issue. He told the House intelligence committee it “should be clear to everyone that Russia brazenly interfered in our 2016 present election process”, though he said he didn’t have enough information to know if it was colluding with the Trump campaign. “But,” he said, “I know there was a basis to have individuals pull those threads.” Mueller found that the Trump campaign embraced Russia’s help and expected to benefit from it, though he did not allege a criminal conspiracy. Durham brought his first criminal charge last week, against a former FBI lawyer accused of altering an email related to secret surveillance of former Trump adviser Carter Page. The attorney, Kevin Clinesmith, pleaded guilty to a false statement charge.