udid number?

My ipod was stolen. I tracked it using icloud and gave the address to the police. The detective, however, says he needs the udid number to prove it is mine when he gets there. How do I get the udid off my computer? No, I obviously cant plug in my ipod and my daughter threw away the original box so I cant get it off of there. I need to find it somewhere in my computer because I even called Apple and they dont have it on file.