eric glisson. we first met him in the spring of 2012 when a "dateline" producer working on a different story in sing sing met eric in his cell. >> you're going to film me? >> yeah. >> he had been locked up for 18 years. >> you want to see what it's like to live in here? i can touch the walls with my hands. >> eric told us he didn't belong here. >> my story is that i'm unjustly convicted for a crime i didn't commit and from february 3rd of 1995 until the present date i've been sitting in here lingering every day wondering whether this mistake will be corrected. >> we've heard that before. many times. but what if he was telling the truth? so, over time -- >> how are you doing, man? >> how did you get up here? >> we began visiting eric. >> what's up? >> you're looking good. >> and listening to his story. >> when i got arrested i was always under the impression that people who are guilty actually go to jail. i didn't believe that i would be convicted of a crime that i didn't do. >> when police put the c