Odds of finding missing bag?

Hi everyone, today mi fiancée lost her bike bag on her way to work at Rice University. We don't know if if fell off the bike or if someone snatched it off her bike without her noticing. What are the odds of finding it? There was only some clothes and food there, nothing really valuable. We are both on exchange, so we don't really know what to do in this case. I'd appreciate any suggestions.