I too would like to see this verifiable evidence. So far all evidence presented of so-called Russian "interference" isn't even remotely credible.
He went to the meeting because Russians said they have dirt on Hilary and admitted it.
Also, There was at least one Russian troll farm targeting voters.
https://www.washingtonpost.com/politics/facebook-says-it-sol...
Russia also has a history of influencing elections in other countries.
Reversing the Magnitsky act is pretty much the number one thing the Russian government would like.
Of course there is nothing wrong with this in itself. But while Veselnitskaya may not have been a Russian official, she was promoting official Russian policy and paid by politically connected Russian interests.
[1] https://en.wikipedia.org/wiki/Natalia_Veselnitskaya#Advocacy...
[2] https://www.grassley.senate.gov/sites/default/files/judiciar... (Note this complaint was made in 2016, before the election)
[1] http://www.npr.org/2017/07/12/536782047/donald-trump-jr-admi...