Bicycle detail

My boy rode his bike to the neighbor's house which was only two doors North of our home. He and his friend parked their bikes near the front door to the house and went inside to make a sandwich. 15 or so minutes later they went back out to retrieve their bikes to find they were both missing. My oldest son was with them and left his bike at home so his was not stolen but our home is set further back on our property. This home is near the street and the main windows to the house were covered with curtains. So no one noticed any individual(s) approaching the house. The bike is only 3 months old and in pristine condition. We purchased the bike at RoadRunner Bike shop off of Broadway in Tucson and they have record and proof of purchase along with the serial number. A Police report has been made.