The FBI formally confirmed in a letter disclosed Monday that it is investigating Hillary Clinton's use of a private email server during her time as secretary of state, describing the probe as "ongoing."
In a Feb. 2 letter to a State Department official, FBI General Counsel James Baker revealed little about the scope or scale of the investigation, and characterized his letter as an acknowledgment of what has been widely reported: That the FBI has been working on matters related to Clinton's use of a private email server.
"The FBI has not, however, publicly acknowledged the specific focus, scope or potential targets of any such proceedings," Baker wrote. "Thus, while the FBI's response to you has changed to some degree due to these intervening events, we remain unable to provide the requested information without adversely affecting on-going law enforcement efforts."
Left unclear is if the probe remains a security review for a potential security breach, or if it has morphed into a criminal investigation.
The probe into the private email server has been a poorly kept secret since last summer, forcing Clinton to defend her actions at almost every turn on the campaign trail. Baker's letter, which was filed in federal court Monday, comes on the eve of the first-in-the-nation primary in New Hampshire.
Attacks from Republican presidential contenders ramped up after the State Department on Friday confirmed that "top secret" information was sent through Clinton's server during her tenure. In fact, the agency said it was withholding 22 of her emails because they were deemed too classified for public release, even with redactions.
For her part, Clinton has insisted that she never used her private email server to handle material that was deemed classified at the time. And she has accused congressional Republicans of using the issue to hurt her campaign.
"As the State Department has confirmed, I never sent or received any material marked classified, and that hasn't changed in all of these months," she said in an interview last month on NPR. "This, seems to me, to be, you know, another effort to inject this into the campaign. It's another leak."