To revive an old thread: I ended up on the other end of a similar situation. Over a month ago I was contacted by "a friend of a friend of a friend" and asked to contact the owner of a recovered iPhone 5S. The story I was presented was that an iPhone was found on a beach in Cuba

and brought back to Russia. Now they wanted to contact the owner to see if perhaps they could unlock it for a modest fee, as to save themselves a trouble of shipping it back to U.S. I did, and after some consideration, the owner wanted the phone back. However, a person who contacted me was not happy with this turn of events and said they'll use it for parts instead. I felt really bad for the whole thing and after some communication with the owner and a swindler decided to be a good samaritan and save the phone and its content (32 GB version, full of pictures from vacation, according to the owner) by paying $200 ransom so I could take the matter into my hands entirely.
Now, naturally I expected the owner to arrange the shipping. However, he insists I arrange and pay for the shipping myself and he will reimburse once he has a working phone in his hands. Naturally, I'm a bit hesitant to "invest" another $100 into this venture without any guarantee from the owner other than his word (he claims to be a police officer and apparently thinks it is enough). His emails often couple of weeks apart, and he wrote me just now again, wondering whether I have cannibalized the phone yet. Still wants me to pay the shipping.
What would you do? Any advice is appreciated.