He’s sworn to never give up his sources, if Julian Assange ever told where he got the DNC emails then it would clear up a lot about the Seth Rich murder.
My belief is that Seth Rich is the source of the emails, he probably had a problem with all the illegality of what was going on at the DNC and gave Julian Assange the emails as evidence and he was murdered as a result.
I believe that Assange has only said "it wasn't the Russians" who hacked the DNC server.
What I recall is that Seth Rich was a Bernie believer.
That he thought that they robbed Bernie(paid him off with a new lake house) of the Dem nomination. He was pissed off about that and so he gave the emails to Wikikeaks.
So, they killed him. Then to shut up the parents they threatened/reminded them that they had another son and it would be a shame IF something happened to him too.