went everywhere together. >> when she started bringing up facts, we were able to corroborate some of the information. >> vera provided plenty of supporting details. how just days before the shooting, she went with elizabeth to a field and test fired the murder weapon. cops later found matching shells there. and how elizabeth dumped the gun that night with a guy from the neighborhood named dee humphrey who was waiting near the house. humphrey was interviewed. he admitted it was true. vera's story added up. >> so everything was believable. >> then vera, just 15 years old, naive, frightened, no attorney representing her, dropped her bombshell. >> vera eventually became aware of, through elizabeth, that joan and elizabeth had had some discussions about killing david shannon, that her mother had attempted to poison david