​Politico said it started receiving emails on July 22 from an anonymous sender. The person identified himself as Robert and used an AOL mail account. The documents that Robert sent to Politico were authentic -- it was a preliminary version of Vance's vetting file. The research dossier was a 271-page document based on publicly available information about Vance’s past record and statements, with some — such as his past criticisms of Trump — identified in the document as “POTENTIAL VULNERABILITIES.”