Bicycle detail

My sister had borrowed my bike and forgot to leave it locked. It lives in a shed behind my house with the washer and dryer. I it is most often locked to my partners bike and our large generator. The chain on both bikes unlocked but only mine was missing. The thief also took a power drill from out tool shelf which is back in the shed. I believe it happened last night - i was in the shower and thought i heard someone coming around the side of our house. This morning when i checked out back the bike was gone.