Yes, I can go along with that… she definitely helped her along. That's why it would make all the more sense for her, and not Carl, to be the one to take Lizzie out when she kills someone else. Carol would have to be wracked with guilt. I think her judgment was clouded by her sense of responsibility to the girls and…

I agree with you, except on one point: I don't think Carol "created" the Lizzie-monster. I think Lizzie is a sociopath. You don't try to suffocate an infant - and appear to be enjoying it - if you've got all your marbles. Same with mutilating a bunch of baby rabbits. So, I do think Lizzie killed Karen and David, but…