Howlin, I don't know if anyone's answered you yet, but I certainly don't remember hearing about the walkman last summer. Perhaps it wasn't cataloged as being missing because the police or friends just didn't think of it, though.
It is possible the LE folks kept this out of the news while canvassing pawn shops in hopes of finding her walkman. This, of course, assumes a level of competence that the DC police don't often display.