What you must be going through just breaks my heart!!!! Wish I could help but I'm in BC, or else I would've.
I too have a suspicion that the people that phoned you have him. Why else would like to know about the history of a recent dog? Sounds too much of a coincidence to me. My heart continues to go out with you. More good vibes sent your way!!!!
Can one protect themselves from this ever happening? By that I mean, short of a watchful eye, perhaps fenced in, and leash on is common thinking. Sometimes in the house I don't know where Bailey is, this is partly due to his small stature (7.5lbs), but still it could've turned out to be a lot of searching if he went o/s w/o my knowledge. Does one just have to wait to see if the dog is brought to a vet; of course assuming that they were chipped?
You are posting and advertising in every way possible that a wonderful mama like you does. How lucky for Ozzy to have you!!
Just thinking that perhaps a neighbor of the people who, perhaps, have him (hopefully they are living in your neck of the woods, so all may see/read the posts up about him) will question them and/or call the police. Good luck in your search and I will be dropping in tomorrow hoping for a 'welcome home' tag. Fingers crossed for you and Ozzy.
Ozzy... where are you???