Story highlights "I think unquestionably if [Clinton] takes office she is going to be under criminal investigation," Johnson said.

"This is Watergate kind of stuff," Johnson said.

(CNN) Libertarian presidential nominee Gary Johnson says he thinks Hillary Clinton could face impeachment over the continued FBI investigation into her private email server if she is elected president.

Johnson made the comment Saturday on KNUS radio in Colorado when asked about FBI Director James Comey's revelation on Friday that the bureau was pursuing an investigation into recently discovered emails belonging to longtime Clinton aide Huma Abedin.

"I think unquestionably if [Clinton] takes office she is going to be under criminal investigation, unquestionably this is going to be the nation's agenda for the entire time she is office and it may well end up in impeachment," Johnson said on "The Craig Silverman Show."

"This is Watergate kind of stuff," he continued. "This is really, really deep, real stuff and all you have to say, all you have to recognize is the FBI would not have done this -- this is not political, this is anything but political, because of the fact they dropped this investigation in July, saying, to clear the decks for the election. That was also clearly, I don't even want to call it a political move, as much as a move that would clear up the election, that people would feel like this was not overhanging. Well, now it's overhanging, and it's overhanging for a reason. There's so much smoke in the room that it will never, ever get ventilated over the next four years. Never."

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