Kevin Cooper: Letter from San Quentin

Nearly 20 years ago a death row inmate wrote to "48 Hours" that he was framed for the murder of four people. Was evidence planted? New DNA tests could answer that question. Correspondent Erin Moriarty investigates. See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.