. >> grandma is sister joanna chan, a mary knoll nun. >> i began working at sing sing more than 12 years this is the battle about general adult. >> grandma volunteers at the prison, working with inmates in a theater program. >> she even teaches them chinese. >> through the years, grandma has helped dozens of men, but she says this inmate here on stage, a convicted killer has changed her. >> he's just so brave. watching him all these years i take such courage myself watching him. >> sister joanna remembers the first time she met this inmate. he was sitting alone eating. >> he said my family sent me 30 pounds of food. i said your family must love you very much. he said yes because they know i'm innocent. and that's how the whole story began. >> a story that began with the unlikely friendship between a nun and a convicted killer would grow into a quest that would shake the faith of even those sworn to uphold the law. >> i thought if he was innocent god has to see him through. so who is this convicted murderer? he is inmate 97a7088, 38-year-old eric glisten. we first met him in the spring of