How do you figure out if an account is fake? You look for certain flags -- the customer is deceased, they're an implausible age, they live at a nonexistent add

How do you figure out if an account is fake? You look for certain flags -- the customer is deceased, they're an implausible age, they live at a nonexistent address, or perhaps the paperwork to create the account wasn't signed. Presumably the 1.4M newly discovered fake accounts had some characteristics which they didn't look for on their first pass. Maybe the paperwork to create the account was signed, but it was all signed by the same bank employees rather than by customers. Maybe the paperwork to create one account got photocopied and submitted as the paperwork to create other accounts. You get the idea...