An FBI official is under investigation for allegedly altering a document connected to the 2016 surveillance of Trump campaign adviser Carter Page, CNN reports. The document, which surfaced during a portion of the Justice Department Inspector General Michael Horowitz's review into the Foreign Intelligence Surveillance Act (FISA) warrants obtained on Page, was reportedly altered enough to change its meaning, according to unnamed sources cited by CNN. But it was not immediately clear what role the document played in the investigation of Page. Horowitz turned over the document to federal prosecutor John Durham, who is conducting the probe into the intelligence gathered for the Russia investigation by federal agencies. The altered document is reportedly a focus of Durham's probe. The identity and employment status of the FBI official is not known. Horowitz's report on the FISA warrants is scheduled for release next month, and the inspector general will also testify before Congress after the findings are released. Horowitz's office and the Justice Department have not commented publicly on the matter.