Huma Abedin, Hillary Clinton's top aide when she was Secretary of State, may have opened herself up to criminal charges for failing to honor an official "separation agreement," which requires her to surrender all work-related documents when she left office.

As it turns out, Abedin retained control of emails she sent and received through a personal email account hosted on Clinton's private email server for almost two-and-a-half years after leaving the agency in Feb. 2013.

However, by doing this and signing the agreement, officially known as the OF-109, Abedin may have opened herself up to criminal penalties under 18 U.S.C. Section 1001 for knowingly and willfully falsifying or concealing material fact in a statement or document submitted to any department or agency of the United States Government.

"I am not retaining in my possession, custody, or control, documents or material containing classified or administratively controlled information furnished to me during the course of such employment or developed as a consequence thereof," the form obtained by The Daily Caller reads.

"I have surrendered to responsible officials all unclassified documents, and papers relating to the official business of the Government acquired by me while in the employ of the Department," it continues.

While it's unclear whether Abedin would be subject to prosecution due to the nature of Clinton's private email setup, the revelation adds to days of reports to the FBI's expanded probe into Clinton's personal server and whether classified information was intentionally falsified or mishandled, according to The Hill.

Furthermore, it was revealed that Cheryl Mills, Clinton's ex-chief of staff, also had an OF-109 form but didn't appear to have signed the form.

Earlier this year, State Department spokesperson Jen Psaki told reporters that the department had no record of Clinton or any of her predecessors signing the OF-109.

"I think we're fairly certain she did not," Psaki said. "We have no record of it."