Luella: Unconcious or Deliberate?

I was thinking that I would try to prove whether Luella Miller is actually conscious of her malevolent, life draining actions. I feel that she is unaware that she's the cause of her helpers' deaths until Lydia confronts her in the kitchen one day. After that, she stops seeing anyone, apparently realizing that she has in fact killed those who help her. So, I hope to prove that up to that point, she did not realize what she was doing. What do you all think?