Just weeks ahead of the US elections on November 9, the FBI revealed it would re-investigate the content of the correspondence.
Now Mr Assange, who is holed up in the Ecuadorian Embassy in London to avoid extradition to the US, said the most damning email yet is about to come out.
In an interview with veteran journalist John Pilger, for Russia Today, Assange said the Saudi Government funds both ISIS and Clinton’s foundation.
He said: “There’s an early 2014 email, from very early on, so not so long after she left secretary of state to her campaign manager John Podesta.
“It states that ISIS is funded by Saudi Arabia and Qatar – the governments of Saudi Arabia and Qatar.
“I think this is the most significant email in the whole collection.”
Mr Pilger, author of Distant Voices and Tell Me No Lies and owner of Dartmouth Films, asked whether this meant the same people who funded ISIS were funding Hillary Clinton.
Assange simply replied “yes”.
He told Dartmouth Films: “All serious analysts know, and even the US government has agreed, that some Saudi figures have been supporting ISIS and funding ISIS, but the dodge has always been that it is some ‘rogue’ princes using their oil money to do whatever they like, but actually the government disapproves.
“But that email says that it is the government of Saudi Arabia, and the government of Qatar that have been funding ISIS.”
Julian Assange accuses Hillary Clinton of misleading Americans about the true scope of Islamic State’s support from Washington’s Middle East allies.