I'm so sorry about the mess and your loss! This behavior is on the upswing, and it's not a pretty sight.
I've gotta share my yesterday story after reading this-- We put our bikes in the shed after using them last weekend. Yesterday my DH went out there, and came back asking "Where is your bike?" I told him it was in the shed and he said NOT! Someone had taken it. I went over to my neighbor's to see if his bike kept under a pole shed was missing, and my DH (the detective) followed the bike trail thru the grass to see where it had been taken. Fortunately, it was left under a tree on the back end of a neighbor's property, so the story has a good ending for us. But we took the warning, and will be vigilant about locking the shed, and keeping records of our equipment that we own.