Is seeing really believing? Eyewitness testimony can be a decisive factor in a courtroom, but what a witness sees - or more precisely, remembers seeing - is not always what really happened. In "Eyewitness," CBS News 48 Hours examines how faded memories can jam the wheels of justice, convicting the innocent and allowing the guilty to go free. Consider the following situations: Dale and Ronnie Mahan: Two Alabama brothers were convicted of kidnap and rape, largely on the basis of compelling eyewitness testimony from the victim. After more than 13 years in prison, they were released when DNA evidence showed that a semen stain on the victim's clothing did not come from either of them. Anne Pope: Despite the DNA evidence used in the Mahan case, the victim continued to be totally convinced that the Mahans are guilty. When the DNA turned out instead to match that of a man with whom she was having an affair, the district attorney decided to retry the case. Then an even more sophisticated test was performed on another piece of semen-stained evidence; the results didn't match the samples from the Mahans or the boyfriend. Late last year, a judge dismissed all charges against the Mahans, who are now seeking $1 million each from the state. Daniel Rubin: After being wounded in a San Diego bank heist, Daniel Rubin was asked by San Diego police to try to identify his masked assailant using his split-second memories. How reliable could he be?