“e officials declined to describe the intelligence obtained about the involvement of a third-party in passing on leaked material to WikiLeaks, saying they did not want to reveal how the U.S. government had obtained the information.
In an interview with Fox News, WikiLeaks founder Julian Assange said he did not receive emails stolen from the DNC and top Hillary Clinton aide John Podesta from ‘a state party.’ Assange did not rule out the possibility that he got the material from a third party. “
Source: U.S. obtained evidence after election that Russia leaked emails: officials | Reuters