Hillary Clinton
Hillary Clinton Reuters

The FBI will re-open its investigation into Democratic presidential candidate Hillary Clinton's use of a private email server while she served as Secretary of State, NBC News reported Friday.

FBI director James Comey made the announcement in a letter to the Senate Judiciary Committee, according to the network.

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

In July, Comey announced that he did not recommend charging Clinton with willfully mishandling classified information.

In September, the FBI chief defended his agency's decision to not press criminal charges in the investigation. Documents related to the case were released just before the Labor Day weekend and included a summary of Clinton's July interview with the FBI about her private email server, as well as a detailed investigative summary of the case.

The FBI language in the letter to Congress makes clear that new evidence has been discovered and thus will be reviewed, meaning FBI agents will read these emails, according to NBC News.

It is unusual for the FBI to tell Congress it is looking over newly discovered evidence in a criminal inquiry that was otherwise closed.

Asked to respond, a top Clinton campaign spokesperson told NBC News, "No idea."

Clinton has said she used private emails out of "convenience", though she has also admitted it "would have been better" to have two accounts to separate work and personal emails.

(Arutz Sheva’s North American desk is keeping you updated until the start of Shabbat in New York. The time posted automatically on all Arutz Sheva articles, however, is Israeli time.)