Ron, he didn't say they had to be the "same" two forms of ID
I would try the reverse look ups too, however, cell phone numbers are usually unreliable unless you "pay" a company to retrieve it and it could come back to the same PO box.
That said, it is amazing to me that the PD, local guys won't do anything?
If you know the po box, you can look on mapquest and see what towns are close. You can put in the guys name and towns, and many times it pops up with their local address, unless they have always been unlisted.