In his first public comments about the Trump-Russia investigation, he said “it would be unfair” to potentially accuse someone of a crime when the person could not stand trial to defend himself.
Breaking his silence for the first time since his final report was published in April, Mueller reiterated that the investigation did not exonerate the president, saying: “As set forth in the report, after that investigation, if we had had confidence that the president clearly did not commit a crime, we would have said so.”
Mueller also announced his resignation from the Department of Justice and the closure of the Special Counsel’s office.
Trump reacted swiftly to the press conference. In a tweet, he said: “Nothing changes from the Mueller Report. There was insufficient evidence and therefore, in our Country, a person is innocent.
“The case is closed! Thank you.”
Mueller’s final report found no evidence of collusion between Russia and the Trump campaign, but left the issue of obstruction of justice to the US Department of Justice (DoJ) to decide on.
Mueller said the written report “should speak for itself” and that he will not speak about the matter again, quashing rumours he would testify before Congress.
He said: “Our investigation is complete... we are formally closing the Special Counsel’s office and I am resigning.”
Attorney General William Barr, who heads the DoJ and was appointed by President Trump, decided no charges should be brought.
Last month Barr released a 448-page redacted version of the 22-month investigation into Russian election meddling in the 2016 presidential election.
Mueller was reported to have complained privately to Barr that he believed a four-page letter from the attorney general summarising his main conclusions did not adequately represent his findings.
Earlier in May, the White House invoked “executive privilege” to block the release of the full, un-redacted report.
Barr now is leading a review of the origins of the Russia investigation in what is the third known inquiry into the FBI’s handling of the matter.
Mueller also reiterated Russia’s interference in the 2016 US presidential election, saying were “multiple, systematic efforts” to interfere and that “deserves the attention of every American”.
Mueller detailed that meddling in an indictment last year, when he charged 12 Russian military intelligence officers with hacking Democratic email accounts.