Object of desire?

Last weekend me and my friends went to Fukuma Beach for Surfing. We enjoyed the time and after changing our clothes we decided to go out in the evening to an Izakaya. We went by bicycle and of course I decided to leave my plastic bag with the wet towel and swimming things in the bicycle basket. I always lock my bike very carefully because it's a expensive and desired one !! After fantastic tabenomihodai it was time to go and I was so lucky that my bicycle was still there, "Japan is a secret place", I thought. Suddenly I recognized, that the basket was empty. Who the devil is more interested in a wet blue stinky silk- swimming shorts than in my bike?