Reunion: Killer revealed.

Disclaimer: I own nothing. This is all the property of Fox network. Since the show never revealed who the killer was, and none of the three stories on this sight even try to aswer that question, here's my theory.

Craig spoke to his son Henry. Henry was out on bail for assaulting detective Marjarino. Craig tried to assure his son that everything would be okay. But there had been so many lies that Henry had a hard time believing anything his father said. Craig decided to tell Henry the truth, no matter how painful it was.

Craig: I will not let anything happen to you. I will go to prison before I let that happen.

Henry: Why does Marjarino hate you guys?

Craig: Twenty years ago I accidently caused the death of his father. I don't blame him for hating me but you shouldn't pay for that.

Henry: Did you try to run him over?

Craig: Yes. If the judge rules there's enough evidence to prosecute, I'll confess. You have my word.

Henry: Marjarino says you killed mom. I know you didn't get along, I know you and your friends are covering something up. Who killed my mother?

Craig: It was your sister, Amy.

Henry: Who's Amy, and how is she my sister?

Craig: Years before you were born your mother had a baby, your uncle Will was the father. She put the baby, Amy, up for adoption. She thought she was giving Amy a better life, she was wrong. Amy's foster father was physically abusive, things got so bad the foster mothr faked their deaths and fled with Amy. But she was mentally ill. All things considered Amy had a bad childhood. She tracked down your mother, blamed her for abandoning her. Amy was messed up,grabbed the gun, and it went off. I don't think she meant to kill Samantha, she seemed pretty distraught. We found your mother at the reunion as she was dying. She begged us to protect Amy.

Henry: You're saying mom wanted you to protect Amy, even after she murdered her?

Craig: Yes. You'll understand when you have kids of your own. We've been protecting Amy because it's what your mother wanted. It's why you can't ever tell anyone what your sister did.

Henry: She's no sister of mine. I want nothing to do with her.

Craig: I'm sorry to hear that. But the same parental instinct that made Samantha ask this of us is also what would make me confess to protect you. Promise me you'll never tell anyone.

Henry: Okay, I promise.

Craig: Thank you. I love you son.

Henry: I love you too dad.