[MarkL]

There was a hacker in Eastern Europe who had hacked Sid "Vicious" Blumenthal's email account, and when some of the messages between him and Hillary were released, that exposed the fact that Hillary was using a private, secret email account, hosted on her own physical server.

Mark

[TigersEye]

OK, thanks. I couldn't remember the hacker's handle but I've got it now. Guccifer.

Hillary Clinton's secret email address is revealed as infamous 'Guccifer' hack exposed some of her messages and the White House washes its hands of the mess 3 March 2015

Some of the messages Guccifer leaked online consisted of intelligence reports, sent in late 2012 to Clinton's back-channel address, and covered matters in Libya - including the aftermath of the September 11, 2012 terror attack in Benghazi.