When I was stationed in NC I sold a Springfield Champion to a guy in my unit, a couple years later he sold it to a guy (with a felony) who ended up using it in an armed robbery and shooting on base. Not really sure how CID got my name (I bought it from a gun shop here in TX) but they called me in. Apparently they thought I was the one that sold it to the criminal but I had my bill of sale and pistol permit (you have to give a pistol permit in NC when buying a handgun, even if FTF) from the other guy. Once I showed them I did the right thing they left me alone.
On a side note: The CID officer had it sitting on his desk while I was talking to him. I tried to see if I could buy it back from them but he told me after the investigation it would have to be destroyed.
