Originally Posted by jbairdjr
Either way, the correct thing to do is try and get it back to the rightful owner.
I would imaging that the address book would be full of people who could tell you who the phone belonged to.
OP stated the phone's screen is locked. You can't browse the contacts on a locked phone.
The cops would store it in the lost/found basket before they auction it.
The carrier can locate the owner by the IMEI number on the handset. Its the best choice.