There is literally no concrete evidence that I've seen yet to suggest anything other than someone who speaks Russian had access to the DNC's system at one point.
No evidence that any of the (apparently several) hackers who had access to the system had ties to the Russian government.
No evidence that Guccifer 2.0 was one of the "Russians" inside the DNC's system and could have easily been one of non-Russian speaking hackers in the system.
No evidence beyond someone's gut feeling that the released documents have been forged.
Someone with a lot of media influence is trying really hard to make this about "Cyber War" between the US and Russia to downplay the legitimacy of the content. These documents ain't fucking PsyOps or counter intel from Putin; they're the fucking DNC and Establishment Democrats getting caught being as corrupt as Republicans are renown for and squirming under the pressure to find an excuse.
"The fucking Russians did it!" is the best distraction they're able to come up with.