In a Congressional hearing, Representative Blake Farenthold (R) points out that it has long been known that the hacker nicknamed Guccifer broke into the email account of Clinton confidant Sid Blumenthal and gained access to hundreds of her emails. Then he asks FBI Director James Comey, “During your investigation, were there other people in the State Department or that regularly communicated with Secretary Clinton that you can confirm were successfully hacked?”
Comey replies, “Yes.”
Farenthold confirms, “And were these folks that regularly communicated with the secretary?”
Comey again replies, “Yes.” However he doesn’t give any more details, such as how many such cases there were, or who they were. (Note that this is the only time Blumenthal is mentioned in Comey’s hearing.) (CNN, 7/7/2016)
A September 2016 FBI report will mention an incident in early January 2013, when an unnamed member of Bill Clinton’s staff has her email account on Clinton’s private server broken into by a hacker.