It will be a tough find for sure. I understand the Pawn shop cant give you the buyer information. Unfortunately the Pawn shop is going to be your only resource. Perhaps give them all of your information and ask them if they will contact the buyer. Maybe offer to cover $$$ there time to do so. If not you could hope for national registration of firearms.
Concentrated power is not rendered harmless by the good intentions of those who create it.
"If you find yourself in a fair fight,,,
Your tactics suck"- Unknown