Theft Description

I am staying in Edinburgh at an AirBnB. I brought the bicycle into the building on the ground floor to park it while i went upstairs to drop my things off. I am convinced the main door was locked, but maybe not? 5 minutes later, I came downstairs to pick it up, and it was gone! My wife claims she saw three young guys on the street corner, one of whom already had a bicycle, just before we went inside.