Editors Note: This story has been updated multiple times throughout the day to reflect ongoing developments.

The Federal Bureau of Investigation has opened an investigation in connection to the Hillary Clinton e-mail scandal.

In a letter (PDF) from FBI director James Comey to lawmakers, Comey said the FBI "in connection with an unrelated case" has "learned of the existence of emails that appear to be pertinent to the investigation." The bureau, he said, is taking "appropriate investigative steps to determine whether they contain classified information."

Comey told lawmakers in his letter that he did not know how long the investigation would take, but the development comes less than two weeks before the presidential election, where Clinton is facing off against the GOP's Trump. The Clinton campaign told NBC News that it had "no idea" what Comey was referencing in the letter, and later demanded that Comey "immediately provide the American public more information than is contained in the letter." Trump said voters should reject Clinton because of her "criminal scheme."

The New York Times reported that "Federal law enforcement officials said Friday that the new emails uncovered in the closed investigation into Hillary Clinton’s use of a private email server were discovered after the F.B.I. seized electronic devices belonging to Huma Abedin, a top aide to Mrs. Clinton, and her husband, Anthony Weiner. The F.B.I. is investigating illicit text messages that Mr. Weiner sent to a 15-year-old girl in North Carolina."

The FBI declined to elaborate, telling Ars "We cannot comment beyond the language used in the letter from Director Comey." Comey's letter, however, said the FBI "cannot yet assess whether or not this material may be significant."

In July, Comey issued a harsh assessment of Clinton's use of a private e-mail server during her tenure as secretary of state, calling her handling of classified data "extremely careless" and suggesting that it was possible her home-based mail server had been breached by hackers.

But Comey at the time closed the case and said he would recommend no criminal charges. He said there was a lack of evidence that Clinton had intended to expose or transmit classified data or that she mishandled information in a willful oversight of her responsibilities.

Comey said the following in July:

Our investigation looked at whether there is evidence classified information was improperly stored or transmitted on that personal system, in violation of a federal statute making it a felony to mishandle classified information either intentionally or in a grossly negligent way, or a second statute making it a misdemeanor to knowingly remove classified information from appropriate systems or storage facilities. Although we did not find clear evidence that Secretary Clinton or her colleagues intended to violate laws governing the handling of classified information, there is evidence that they were extremely careless in their handling of very sensitive, highly classified information.

Trump has said that Clinton would be in jail for using private e-mail if he were elected. Before a New Hampshire speech Friday, Trump uttered the "criminal scheme" remarks and said that "Hillary Clinton's corruption is on a scale we have never seen before."

House Speaker Paul Ryan, (R-Wis.) tweeted that Clinton should be suspended from any classified briefings and that she "has nobody but herself to blame. She was entrusted with some of our nation's most important secrets, and she betrayed that trust by carelessly mishandling highly classified information."