Oooh! WTF is wrong me?
Well, your overblown drama aside (complete with six question marks for full effect...), I know from experience that if you want to make sure that the lost property has any chance of getting back to it's rightful owner fully intact, you hand it over to the local authorities. Makes sense when you chew it over, doesn't it?
Of course you could instead just leave it where you found it (not very neighborly, though). What you can't do is take it home and sell it.