>> now, elizabeth? i could see it. >> elizabeth? the shannons' 15-year-old daughter? is it possible she was a cold-blooded killer who executed her very own stepfather? the man who adopted her, raised her, provided for her? maybe, said david's sister brenda. daisy and elizabeth were always troubled, said brenda. and when elizabeth hit her teens, watch out. >> david and joan did not have the tools needed to deal with what those two girls dished out. it was boys, drugs, violence. if she got angry, she would destroy something of theirs. >> that was hardly elizabeth's view of things. she conceded she was no angel. she acted out all right, never denied that. but elizabeth always claimed it was the adults who made it ugly and hostile at home, where