stolen Jamis Citizen

My blue-green Jamis Citizen has a unique contraption attached to the seat post. It looks like a piece of grey plastic tubing with the metal clasp to a dog leash sticking out of it. I would use this to attach my dog's leash to my bicycle. The contraption was homemade and irreplaceable. The bike has a padded seat, a small headlight, and a metal rack with a spring-loaded clamp mounted over the rear wheel. I lent the bike to a kid I barely know, and he apparently left it unlocked while he went in somewhere to use the bathroom. It still had the locks attached to it: a black U-lock mounted on the frame and a grey cable lock with a padlock mounted under the seat. Please, if you see my bike, contact me. The homemade dog leash contraption is irreplaceable, and I need it to go places with my dog!