i dont mean to over emphasize what i had previously posted, but just in case you hadn't read it, you can call your service provider, and they can sometimes TRACK your cell phone for you, which will give them a lead to the culprit!!!
I had just read that your cell phone was in the bag, so i hope you read this!
my friends backpack was stolen, and he called his phone company, and they were able to locate his backpack with most of the stuff still in it, including his phone!
Yeah i did that when I was in the police station. The phone company said they can't track it. Why? I don't know. But i think the phone was off or maybe was throw away somewhere. They said they can't. I wish they could....like in some of those FBI movie.