The Desk Conflict

Many of you have heard word of this already: After I got my desks, one for each office I am in, there has been a conflict over the use of it. In each office there is at least one enemy that is putting objects on my desks. There is a clear difference between the way I organize my desk (Nothing is on it) and the way others organize theirs (Full of stuff). While I am out of the office, someone will put things on my desk or they will work at my desk. Working at my desk is not a big deal, but there is an enemy out there that wants to muck up my desk. I will take whatever is on my desk off and put it away and when I come back after a day or so there will be more stuff at my desk again. I need to do some recon and espionage and get to the bottom of this. I smell a rat.