and one person only. >> according to lynn sa cover, sabrina's story was a web of lies.oven together by a deranged and troubled teen whose fantasy of having a life with kevin and hailey pushed her over the edge. >> i think she imagined the relationship that didn't exist. it was like i want this so this is how i'm going to get it. >> as for the alleged affair, did you ever see any hint of anything appropriate between kevin and sabrina? >> absolutely not. >> no, no that's not my brother. >> sabrina, they said, turned on kevin and blamed him for everything hoping for a plea deal. >> so what's going on here? sabrina lying to save her own skin? >> absolutely, absolutely. >> not according to detective parmertor. >> you're convinced there really was a plan between her and kevin? >> yes. >> and that there was affair, despite the lack of hard evidence. >> she had no proof. there's no love letters. >> no. >> there's no photographs, there's no vitt videotape. >> no. >> how do you know it happened? >> took sabrina on her word. every time we interviewed sabrina, she always told us th