I guess I assumed these were coming from out of the country. Do we know that they are being mailed in the US? If that is the case the postal service almost certainly knows which post office these were mailed out of.
Could be useful if triangulated with other information.
And it's always possible that whatever mailbox they dumped them in was in view of a video camera or perhaps their car passed video surveillance (or walked by). Or maybe used an ATM nearby. Or paid a toll. People slip up. For that matter what about all that stuff about embedding things in printers (micro traces or whatever they are called).
Otoh, I constantly get all sorts of scams from overseas wanting to charge me ridiculous amounts of money for trademark registries (approx. $2000 USD iirc) of zero value. They have been pretty consistent over the years and I'm guessing that even with the cost of foreign postage they are a net win for the perps. Otherwise I can't imagine they would keep sending them.
