Yes, I believe Rudi is correct, but only after the "A" carrier can satisfactorily demonstrate that they successfully delivered to it "B"! Thus you sometimes get a lttle "rigamoroll" & fingerpointing or whatever!

Also International, as you know, is is bit more complicated, as it is generally, in my experience when it is not a US carrier responsible to begin with!

Hopefully you'll have no worries here- and fortunately you did get the luggage back!!!