john petrey, who was the chief assistant d.a. for dekalb county, georgia.y had much at all until the u.s. attorney's office did, in fact, bring the boxes to us. and i was able to find an empty store room in the courthouse and created, what i called, a war room for this case. so i buried myself in this office, started going through the file. >> one thing was clear, hinton had been their key suspect early on because he had a criminal record. as petrey began poring through the file, he came across a name, tammy singleton. she sat down with us to tell the same harrowing story she told to the fbi. >> really small town, everybody knew everybody. >> back in 1982, 12 years before shannon's disappearance, tammy was 14 years old and living with her family in neponset, illinois. one day she got a call from the brother of her ex-boyfriend. the brother was 22 years old, already married. he asked tammy to get together, and she agreed to meet him on her way to a slumber party. >> i'm waiting around with my overnight bag, and he finally pulls in, doesn't see me initially,