Story highlights Clinton expressed "relief" that a Justice Department investigation did not result in criminal charges

"I certainty did not believe that I received or sent any material that was classified," Clinton said

Washington (CNN) As the State Department reopens its investigation into Hillary Clinton's use of a private email server as secretary of state, Clinton reiterated on Friday that her use of personal email was a "mistake" that she would "certainly not do again."

In an interview with CNN's Wolf Blitzer, Clinton expressed "relief" that a Justice Department investigation did not result in criminal charges, and also suggested that she expects the State Department to take into consideration the Justice Department's conclusions.

"It was a mistake for me to use personal email. And I regret that. I am certainly relieved and glad that the investigation has concluded but I also know how important it is to make sure everybody understands that I would certainly not do that again," Clinton said.

Clinton noted on the State Department probe: "I assume they will pursue whatever process they think is appropriate and I also assume that they will pay very close attention to what the findings were of the Justice Department investigation."

Clinton, who has in the past stated that she "never sent or received" classified materials on her personal email server, appeared to soften that language on Friday. "I certainty did not believe that I received or sent any material that was classified," she told Blitzer.

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