I'm not buying this for a minute.
From past stories like this, an 18 yr old boy would have likely just wanted to run off with her.
When it gets this nuts, the girl instigates it.
That's how I'd bet. I think the evidence will confirm it.
The boy is going to do 25-Life, and the girl gets a pass.
--Travis--
Except that David Ludwig had made a video planning to murder people with his friend.
I don't doubt that kara (Lizzie) Borden mentioned to her boyfriend at some point or another how much she hated her parents.
I wait further evidence before weighing in on her criminal culpability. She is morally culpable for their murders.