I found a locked iPhone. Can I sell it on eBay?

A couple months ago, I found a password locked iPhone. I called ATnT to see if I could get the contact info of the owner so I could return it, but for some reason even with the SIM number they couldnt get the info. They told me if the owner called looking for a reported found iPhone, they would contact me. This was 2 months ago. Now Im ready to get this waste of space of my hands, but is it legal? I dont want to get in trouble for selling this property I found then get accused of selling "stolen" property. Also, is there a market for password locked iPhones? Are there people who would be able to unlock it and make it useable? Thx in advance for your answers.