When a big bear of a man in flip-flops showed up with a bottle of Japanese whiskey promising to deliver evidence implicating some of the world’s richest and most powerful men in an epic cover-up of sexual misconduct, our reporters were hooked. The man went by a pseudonym, Patrick Kessler, and he said he had terabytes of video surveillance from Jeffrey Epstein’s residences and other materials that, if true, would validate theories Epstein was engaged in an extensive blackmail operation. Kessler said he would share it all with The New York Times.