The FBI will investigate new emails related to the probe of Hillary Clinton's personal email server after discovering "the existence of emails that may be pertinent to the investigation," according to a letter from FBI Director James Comey.
The letter to congressional leaders, reported by multiple news organizations, does not specify what is in those emails or what the FBI will investigate, and says they were discovered in an unrelated case. He wrote that the agency would be reviewing the emails to determine whether they include classified information "as well as to assess their importance to our investigation."
The "FBI cannot yet assess whether or not this material may be significant, and I cannot predict how long it will take us to complete this additional work," he added.
When the FBI completed its initial investigation over the summer, Comey had concluded that Clinton and her aides acted carelessly, but had not engaged in illegal activity that rose to the level of an indictment. He advised the Department of Justice against prosecuting.\
GOP lawmakers responded with harsh criticism of the director, accusing him of not holding Clinton to the same standard to which the FBI would hold others if they were caught mishandling classified information.
The new development is likely to a big problem for the Clinton campaign, refocusing voter attention on an issue it had been able to argue had been closed.