Sometime in August. Russian Alfa Bank communicated 2,500 times with Trump server mail1.trump-email.com which was not sending anything–that’s unusual. Those that discovered this wanted it public so they gave the info to reporter Eric Lichtblau of the Times in Aug 2016. A Times lawyer contacted the FBI who asked The Times to delay publishing. On Sep 21, 2016 Eric contacted Russian Alfa Bank for comments, and two days later the Trump campaign took down the server. No one from The Times notified the Trump Org. The assumption is Russia did, and that’s very interesting.
Unverified: We are awaiting confirmation. Interesting article by the New Yorker asserts a link between Russia and the Trump campaign.