She was responding to a volley of questions on the surrender of Paul Manafort, Trump's former campaign manager, who has been indicted on 12 counts by a special counsel investigating into alleged Russian interference into last year's presidential elections.
Also announced by Mueller was a guilty plea by George Papadopolous, a former Trump campaign foreign policy adviser, to making false statements to Federal Bureau of Investigation agents.
The Press Secretary also repeated Trump's current favourite go-to line, that the real investigation should be about Hillary Clinton, Uranium One and the pee dossier.
Sanders was defiant about the Papadopoulos guilty plea on Monday.
"Today's announcement has nothing to do with the president, has nothing to do with the president's campaign or campaign activity", she said.
"It has nothing to do with the campaign, it has to do with his failure to tell the truth. That doesn't have anything to do with the campaign or the campaign's activities". Papadopoulos, Huckabee Sanders claimed had an "extremely limited" role.
Additionally, Sanders' repetition of the word "volunteer" to show reduced significance rings hollow in light of the fact Manafort also worked on the campaign for free and is now accused of, amongst other things, "conspiracy against the US".
However, Papadopoulos was not taken up on his offer, and no meeting between Trump and Putin occurred during the campaign. "He reached out and nothing happened beyond that", she said.
John. Q Sarah can you just explain what George Papadopoulos' role with the campaign was?
And there is a hint that Papadopoulos may be the beginning of Mueller's effort to bring charges against Trump campaign officials.
On Monday, Sanders tried to steer the news conference toward Republican plans to reform the nation's tax code. The press secretary said the White House does think it will wrap up soon because the "facts are on our side". "And he was dismissed not long after that", Sanders said. "The House is likely to consider the bill week of November 13th".
Sanders emphasized that she's "not sure that the president recalls specific details" of a March 31 national security team meeting at Trump International Hotel in Washington, D.C.in which Papadopoulos was present.
Judge Colleen Kollar-Kotelly, ruling that the ban would likely be found unconstitutional, issued a primary injunction halting Trump's ban on transgender service members and recruits.