(CNN) -- Thomas Hagan pleaded his case for freedom: To return to his family, to become a substance abuse counselor and to make his mark on what time he has left in this world. He was dressed in prison greens as he addressed the New York parole board. He had been before that body 14 other times since 1984. Each time, he was rejected. Hagan is no ordinary prisoner. He is the only man to have confessed in the killing of Malcolm X, who was gunned down while giving a speech in New York's Audubon Ballroom in 1965. "I have...