I own apartments also and lost an 18 volt dewalt drill. Could that be mine that was stolen and repainted? Maybe there is a tool chop shop operation in one of you units! You would be surprised the things you can find in apartments, stairways and the adjoining parking lots. I usually just hold them for a while then figure they are mine. I find many apartment dwellers do not even think about things like this, they just buy another one. Do you have any tenants that could be on vacation now and have not even seen you signs yet?