OMG!
I can't believe that the person who TOOK yoshi is reading all this and not caring. This person has not heart.... S E R I O U S L Y ! Its good you got the police involved in this THEFT.
Is your Yoshi microchipped? If so you should let all the vet around your area know so that they can scan every single yorkie that comes in just to make sure the yorkie belongs to the correct owner. And let them know that you have the police involve... I'm sure you can work something out with them. I hope you find him SOOON!