Wisconsin Gov. Scott Walker says the controversy still swirling around him was “old news.”

“If you look at the facts out there, this is old news. This is about a case that was closed last March. A Democratic district attorney in Milwaukee County spent multiple years looking at all this information,” the Republican governor said on “Fox News Sunday.”

Last week, more than 20,000 emails were released from Walker’s time as Milwaukee County executive — emails that suggested Walker and top aides used a secret email system to communicate. Six people in Walker’s political orbit were convicted in an investigation led by District Attorney John Chisholm. Walker was never charged.

(POLITICO's Sunday show recap in 90 seconds)

Walker declined to answer whether he personally used a secret email system, saying instead that the case was over. “You had a Democratic district attorney spend almost three years looking at almost every single of one those communications, interviewing people, talking to people and closed the case last March,” the governor said.

Walker added that Democratic operatives at the Democratic National Committee and the Democratic Governors Association were raising the issues to distract from the successful record of Republican executives.

“Last year, in March, he announced the end of that case. Plain and simple, it’s old news," Walker said. "We have our political operatives at the DNC and the DGA that desperately want to switch the subject from the fact of things like us taking a $3.6 billion budget deficit and turning it into a nearly billion-dollar surplus."

“They desperately want to switch the subject on a subject that’s already been resolved as of last March,” he said.