The FBI has refused to divulge details about documents recovered from Hillary Clinton’s private email server, claiming that the documents are evidence in an ongoing investigation.

"All of the materials retrieved from any electronic equipment obtained from former Secretary Clinton for the investigation are evidence, potential evidence, or information that has not yet been assessed for evidentiary value," the FBI wrote in a filing with a federal court on Monday. The comments do confirm long-held suspicions that the FBI was able to recover material deleted by Clinton or her staff.

The filing is the latest development in the far-reaching investigation of Clinton’s conduct as Secretary of State from 2009-2013, which includes her illegal private email server, her handling of the Benghazi attack, potential disclosure of sensitive information, and the destabilization of several North African and Middle Eastern countries under her term. The Democratic presidential nominee has repeatedly referenced her experiences as secretary of state to demonstrate her mastery of foreign policy issues.

Clinton continues to downplay the investigation, claiming it is a "security review" rather than an inquiry into potential criminal activities. FBI comments contradict this assessment, stating it is a "security referral made for counterintelligence purposes" by the inspector general of the intelligence community.