There may be extra steps in between, but if you're tracking a transaction / relationship type which happens twice or more, you can expect that the person on the record is the person you're after or can point you at them.
But I don't know why they expect FBI to actually have it implemented. The system would have to be so widespread/common that we'd know if it existed. I mean, there's https://en.wikipedia.org/wiki/Currency_bill_tracking but that's for hobbyists. Otherwise banks may check for duplicate numbers... but I can't find any mention of more widespread tracking.
