I dno, the motive is something we don't know, what If Bethany was his sister, there's clearly a little boy in the family photos. The boy is tan. What if they both went into foster care,

it was Sarah Harvey in the grave, and he's A, and giving Bethany all the experiences she missed out on in the doll house.

I'm only going on where Marlene said we would even find out why they got lead to Sarah Harvey, or at least about her. The only way would be relevant and not another random missing person, is if she went in the ground, instead of Bethany.

B. hits Ali, jessica sees, does a cover up. Easier than she though right? But she has a wetness I deal with, maybe she took Sarah , before or after Ali. A fight happens .... Bethany wins, or maybe Sarah was her friend. And there's more to the Ali's side she's still not saying. Like Ali hit Sarah first thinking it was Bethany. Bethany enraged, attacks Ali, jessica covers it up. And Bethany runs. Melissa stumbles on to the body. Panics for a bit. Ali is pulled out of the grave. Then replaced shortly after.

Bethany only hears of Ali and nothing about Sarah, only that she's still missing. Maybe Sarah ran too, but she soon finds out that Ali is alive

I can see Bethany . Reaching out to the only person she knows ever really loved her. Boom Caleb. She's spent some time hiding out tracking him down. Chasing Ali, Cuz bitch gotta pay for it. But not to intensely there's these other people wanting to take Ali down, so BIG A doesn't need to get dominate yet. and Caleb takes care of her, But Ali comes back, Shana gets killed. And Bethany Is soo up set because she is the one still hiding, but they know have to make people thinks she's dead, or someone might look for her. And she also knows for sure now its Sarah in the grave. (Maybe Caleb knew different and was trying to get Ali from the start)

This is where Caleb needs to come back full time. Caleb fixes the testing, switching DNa samples . And hacking . They know ahead of time when the new will be broken. So he comes back, shoots a "if looks could kill " at Ali . Toby's house explodes . And boom . Caleb is back in town being big A .

Flash forward to the doll house, Bethany obviously deprived of a natural childhood, want to take the girls away from Ali, and play. She not mentally sound, but how can Caleb let her down, after letting her get locked away,.

Some where Along the way he also cracks, but he's meaner, and Beth is child like.

Also She's BV, at least for her own funeral

I don't know if I think this will happen, but that's how Caleb could be A .