All of the business checks that TPD, I and others around southern MD have had stolen were not stolen by mail carriers or stolen out of any mailbox anywhere. We take our checks to the local post office and mail them directly from inside the building. The thefts can only be occurring at/within the one place that all the southern MD checks are sorted and distributed onward.
Furthermore, the theft operation is highly organized, coordinated and protected. The stolen checks are quickly moved to operators that have an inventory of stolen personal information sufficient to allow them to establish fake bank accounts all over the country, in the name of individuals that have no clue it even happened. Once the account is open, the altered stolen checks are electronically deposited and when the deposit posts, the money is then quickly moved onward to "safe" accounts by the least traceable means.
All of the above makes it damned certain that many/all senior level sheetheads in the Waldorf facility, and probably others, are involved. The USPS has evolved in to being a major crime syndicate.