The federal investigation into Hillary Clinton's private server and her transmitting of classified information was revived Friday, as FBI Director James Comey sent a letter to congressional leaders and relevant committee chairmen that new evidence has emerged in the case.

"In connection with an unrelated case, the FBI has learned of the existence of emails that appear to be pertinent to the investigation," wrote Comey.

"I am writing to inform you that the investigative team briefed me on this yesterday, and I agreed that the FBI should take appropriate investigative steps designed to allow investigators to review these emails to determine whether they contain classified information, as well as to assess their importance to our investigation," he added.

Comey also made it clear the FBI has not thoroughly examined all the new evidence, since it just came to his attention on Thursday.

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"In connection with an unrelated case, the FBI has learned of the existence of emails that appear to be pertinent to the investigation. I am writing to inform you that the investigative team briefed me on this yesterday, and I agreed that the FBI should take appropriate investigative steps designed to allow investigators to review these emails to determine whether they contain classified information, as well as to assess their importance to our investigation," stated Comey.

Subsequent media reports contend the newly discovered emails were not withheld by Clinton and are not even from her server. Instead, it appears the emails are part of the federal probe into the sexting of former Rep. Anthony Weiner, D-N.Y., the estranged husband of Clinton confidante and former State Department official Huma Abdein.

The letter comes just 11 days before the 2016 presidential election, so experts believe there has to be something significant here.

"Well, it couldn't be a trifling thing, because this is a big deal. You can see the brouhaha this is causing, so it couldn't just be a little incident over email. It has to be pretty significant," said Victoria Toensing, a former deputy assistant attorney general of the U.S. and a former assistant U.S. attorney.

She suspects agents came directly to Comey with evidence he could not ignore.

The interview:

"It must be pretty significant if FBI agents took it to him and said, 'Hey, you've got to look at this.' Given all the criticism that has come his way over how he's handled the investigation, I can't see that he would have said, 'Oh well, just go away guys. We've already done this.' He would have had to address it," said Toensing.

Toensing and her husband, former U.S. Attorney Joe diGenova, have publicly discussed the number of career FBI and Justice Department employees who are disgusted that Clinton was not prosecuted for her "careless" handling of classified information and that Comey refused even to recommend charges. She believes Comey may have acted Friday with that internal criticism in mind.

"I think he's felt the heat. If nobody had criticized him at all he might have made this go under the rug. He knows he's in a glass house," said Toensing.

While the Weiner connection is raising eyebrows, Toensing is disgusted that agents only stumbled across this material in a separate case.

"You would think that a competent FBI would have looked at that from the get-go, since it's not a secret that he was married to her top aide," said Toensing.

"This should have been a part of his investigation. Duh. Anthony Weiner is a known risk. He's a weirdo. They didn't look at those kinds of things while they were doing the Hillary (probe). He said it was a thorough investigation. I don't think so," said Toensing.

When asked if Weiner's possible lack of clearance to see any classified materials may get Clinton in trouble somehow, Toensing says that issue has already come up multiple times and the FBI didn't seem bothered by it.

"But nobody had clearances. The lawyers handling this case didn't have clearances. The IT people who worked on her emails, which were all highly classified, did not have clearances. This is not necessarily new. It's disgusting for those of us who have clearances," said Toensing. "I've never seen such incompetence in handling classified information."

She also says WikiLeaks and other revelations paint an even uglier picture than we already knew about the actions of the Clinton Foundation while Mrs. Clinton was secretary of state. Toensing points out that Bill Clinton made $6.2 million in speaking fees from foreign entities with business before the State Department over those four years.

The news comes at a bad time politically for Clinton, since this latest chapter of the investigation likely won't be resolved before election day. At the same time, there will be no government conclusion she broke the law prior to Nov. 8 either.

"Toensing says none of this is good for Clinton's campaign.

"I don't really think it does cut both ways. The fact that there's no resolution is even worse for Hillary Clinton," said Toensing, noting how much a late admission of an old drunk driving arrest nearly derailed the 2000 White House bid of George W. Bush.

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