This is why we need regulations to stop these scammers to raise funds and disappear without consequences.
Usually, a particular investor will just be surprised after those scammers are gone. When they were promoting their project, everything seems alright, legit and something was really going on. But once they got the money and overwhelmed by greed, then, you know what's next??? Running, hiding away from investors. And those investors invested because they did believe that they will get something out of it. And in the first place, no one can say at the very early stage that they are fraudulent, only at the later stages, once the dust settled in.