Actually no, it often is not how it works. For example, Harvey Weinstein's behavior has been "open secret" in certain circles way before the scandal exploded. Epstein has been known to be super shady way before he found his end in prison. Anthony "Carlos Danger" Weiner has been known for his exploits well before he finally was prosecuted. There are, of course, opposite cases, where certain sociopaths meticulously cultivate their benign image and hide their true colors. But often, the true colors are known if not widely, then at least by many people surrounding them. For a reasonably public person, it would be quite hard to lead a double life for a long time without anybody at all knowing.