Putin is not stupid, he's keeping his hands clean, but working his crap behind the scenes so he can't be directly pinned for anything having to do with Trump.
Some evidence is there, but, now they have to play connect a dots to tighten it up and make it waterproof. The strings are there, now they got to tie them together.
Comey's testimonial nails Trump with his own words. Comey is also pissed because of Trumps accusations toward the FBI. There is some truth in those extraordinary claims.