Can someone please explain to me how this happened? What was the scam? He lost peoples money but still doesn’t have any for himself? Not a very good con man.
Short answer is he over-leveraged the exchange he was in charge of. He was using funds that should've been untouchable to do things like buy superbowl commercials, bail out other failing exchanges, cavort with Tom and Giselle, etc.
Longer answer is he used to be in business with the guy who brought him down. They developed a more contentious relationship since then. To dissolve their former biz relationship, bankrupt asshole gave whistleblower asshole a bunch of bankrupt asshole's company's crypto token. Whistleblower asshole suspected bankrupt asshole of smacktalking rivals to gov't regulators and knew that bankrupt asshole's books were wonky. Whistleblower asshole let everyone on twitter know he was selling off bankrupt asshole's shitcoin, knowing that price would collapse and cause a run on bankrupt asshole's exchange. There's obviously a few more elements, but that's the gist.
BTW, I use the term "bankrupt" very loosely here. He is still likely worth north of a billion dollars... though he could possibly be going to jail soon.