You will no doubt recall the sad story of Seth Rich, the DNC staffer who was found murdered on the street outside of his home. Just 12 days after his death, Wikileaks released the emails that proved Hillary Clinton and the DNC were conspiring to destroy Bernie Sanders. These were, obviously, obtained from mysterious sources. Almost immediately, there was speculation that Rich might, in fact, be that source.
That didn't fit the narrative, though. The official Democrat line has been - and remains - "Evil Russian hackers conspired with Trump to destroy Hillary because she would have been such an amazing president."