>> no, it's not. çñ >>> in the spring of 1980, police were still reluctant to listen to camille bell.> children were dying on the streets of atlanta in the daytime. >> among them, jefferey mathis, only 10. like yusef bell, he walked down the street on an errand to this gas station to buy cigarettes for his mother. she never saw him again. >> what we had here was a predator. and what he was looking for was somebody who was cut off from the herd. and if you don't realize you're in trouble until you're in trouble, then you have no way of getting out. >> it would be another year before jeffrey mathis' body was found in the woods, miles from his home. his mother would join camille bell in forming a committee to confront the city's leaders. >> the reaction of the police was that we were overreacting and that there was no serial killer. >> even though by now six black children were dead, four others were missing. >> perhaps we were like distraught parents that really needed everyone's sympathy, but nobody needed to do anything. >> for years, it has been a dirty little secret among the press

camille bell. >> even if it takes 30 trials, i don't care. you know, prove it. >> the prosecutor's answer, it would serve no purpose. >> you can only serve one life sentence. >>> just ahead -- a new alibi that backfires. >> he was out that night, no question in my mind. he was not at home. he was out and about. >> and after all these years, new dna evidence. >> it probably would exclude 98% or so of the people in the world. >>> four years after the trial, robert henry would change his story about seeing the last victim nathaniel cater holding hands with wayne williams. in this affidavit, henry wrote, if my life depended on it, i could not say the man i saw with cater was wayne williams. our producer confronted henry with that affidavit. his signature is at the bottom. >> yes, that's my handwriting. >> whose words are those? >> they're not mine. >> whose words are they? >> i'd rather not say. >> in the summer of 1986, henry was in prison here when he said an associate of wayne williams came to see him and told him what to write. >> when you sa