Re: Evidence it was the Russians what dunnit
I'm sorry to see some reflexive downvoting on your post as it's entirely factual. The CIA have a history of lying - including to their own government (example, they lied about their use of torture to a House Committee) and interfering with multiple country's democratic processes. They have a long and documented history of such. They even ran drugs to finance themselves independently of US government funding. In contrast, Wikileaks provide substantiated information and as far as I'm aware, have never been caught lying about such matters. Wikileaks say it's not Russia and was in fact a leak from within the DNC. CIA say it isn't but refuse to provide evidence - again, even to their own government. (The Chair of the House Intelligence committee was refused a briefing from them when he requested one).
Any logical and evidence based balance of probabilities would be to say that Wikileaks is more likely telling the truth.
And if it is a leak rather than hacking, then the immediate logical follow-up is that the CIA will want to prevent the truth emerging. Someone willing to leak that data is also someone who could plausibly confess to it. Seth Rich is one of the suspected sources of the leak. He could demolish the CIA's entire case by going public as the source. Or rather he could before he coincidentally died a few miles from his house in an alleged robbery. Fun fact: people who mug you for your wallet and phone are usually content to just get those items and run. They don't normally go out trying to shoot people dead. (Especially, you don't normally find their victims dying from multiple shots to the back).
So again, it's a shame to see some people go "Conspiracy Theory" and vote it down (or do so for other reasons). Maybe my post will be too, but there's nothing in the above that is implausible nor flawed reasoning. What it comes down to is that some people don't want to accept the liklihood that people in the US government are willing to have someone killed to suit their agenda. Despite that such people have knowingly killed hundreds of thousands with wars like Iraq or the bombing of Libya knowing full well that such loss of life would be the result. To reject the idea that the CIA or similar would assasinate someone or that people in government would turn a blind eye to it, is to reject countless historical cases where they have done exactly that, and on far grander scale than one life.
In short: which group has the greater credibility - Wikileaks or the CIA. Based on evidence one has to say the former. If the former is telling the truth is it the case that US parties have the motive and demonstrated willingness to dispose of someone who could expose them. Overwhelmingly yes to both of those again. None of this is unsupported so downvote away!