That's some damning prose, but who wrote it? I couldn't find anything on the document identifying the author or office. Given the nature of the material I can understand why, but as it is I see an anonymous paper with no confirmation from outside sources. That will take time.
The document was passed on to the FBI by Senator John McCain and was put together by a former intelligence officer that has deep contacts in Russia apparently.
https:// www.theguardian.com/us-news/2017/jan/10/fbi-chief-given-dossier-by-john-mccain-alleging-secret-trump-russia-contacts
edit- put break in URL to get past spam filter.
Senator John McCain passed documents to the FBI director, James Comey, last month alleging secret contacts between the Trump campaign and Moscow and that Russian intelligence had personally compromising material on the president-elect himself.
The material, which has been seen by the Guardian, is a series of reports on Trump’s relationship with Moscow. They were drawn up by a former western counter-intelligence official, now working as a private consultant. BuzzFeed on Tuesday published the documents, which it said were “unverified and potentially unverifiable".
McCain obviously took it seriously but as you say confirmation is still lacking which is why investigation free from Trump interference and obstruction is needed. Given the nature of what's going on it's unlikely many of these sources will come forward publicly, for the Russians it would mean almost certain death at the hand of Kremlin controlled assassins as with so many who have tried to expose the Putin government such as Alexander Litvinenko and Anna Politkovskaya.
We can see the broad outlines of what has been going on in secret such as the Russian attack on the DNC servers and releases of information gathered there timed to benefit Trump to the greatest degree plus all the well documented contacts between the Trump campaign and White House and the Russian government that resulted in the resignation of Trump's national security advisor before he'd ever really taken his position.
There's one hell of a lot of smoke here for there to be no fire, and clearing away the smoke to see the detail of this criminal act is going to take time and effort. And all the while Trump will be doing his best to create as much chaos and confusion as he can in his and Putin's interests.