CNN's John King said on Sunday that the scandal over Hillary Clinton's secret email server "has new legs" — and that the Democratic candidate has only herself to blame for it.

"The Hillary Clinton private emails controversy has new legs and the Democratic frontrunner has only herself to blame," King said on Inside Politics.

Last week, the State Department confirmed that Clinton did not turn over at least 15 work-related emails from her time as secretary of state. Clinton was supposed to turn over all work-related emails she sent from an undisclosed email server discovered earlier in the year. The contents of that server have since been destroyed by the Clinton team except for the incomplete paper record it turned over to the State Department. Clinton has repeatedly guaranteed that all of her relevant work-related emails have been turned over to the State Department.

According to King, this opens Clinton to accusations of further malfeasance.

"Secretary Clinton can't definitively prove there aren't additional things that should have been turned over to the government but were not," King said. "She can't prove that because she erased her private email server without any independent supervision."

At the heart of Clinton's email scandal is that she made herself the arbiter of what would be sent to the government, and therefore reviewable by the public, and what would not be.

"This would not be an issue if Clinton hadn't erased her email server," King continued. "It wouldn't be an issue at all had she followed the wishes of her boss, President Obama, about how to handle cabinet level email."

Clinton's private email scandal has contributed to the public perception of her as untrustworthy and dishonest.