A girl stole my wallet what should I do?

I was in the classroom and i teacher called to my attention so i can see my grade for the marking period so far. I went up and I accidentally left my wallet on the chair. Then a girl from my class saw and claimed that she was playing around with the wallet and then she putted it into my book bag. At the time I didn't know about it and a few seconds of me going down the stairs i realized that and looked in my book bag when I went back to the classroom to search for it. It wasn't there and the only explanation is that the girl took it so should I accuse her or not cause there was a lot of money in that wallet.