Someone stole my pet and then tried to scam me with it

A woman created a facebook account and then send me messages from it, with pictures of my pet even, when I got tired of playing her game (she wanted me to pay an amount or get her a new puppy), I went to the police, they say they cant do anything, and the woman closed her facebook page, I need to track her to find my dog, an email at least to find the IP and track her,do you know how to do that?