A sawed off shotgun is a Title 3 federal violation under ATF regulations. They are required to be registered just as if it were a suppressor or a full auto weapon. Thanks for letting us know you’re a federal criminal also. Does ATF know you had (or have) this sawed off shotgun? They would certainly be very interested. I’ll give ‘em a call for you. I still have some buddies here in ATF I used to work with. I’ll get an answer for you and let you know what to do next.
I think a complaint to the moderator to contact the ATF is warranted.