She expressed regret, though. She cried when she saw the dead cat. She HAS a mental problem and called herself a failure and I doubt she does it simply for the pleasure of killing a cat. She forms unnatural attachments to these corpses and decides to keep them instead of cremate them. Creepy as ****. But seeing as she is not of the right mind, I wouldn't hold it against her. She DOES need SEVERE help SOON, though, and what she is doing is wrong beyond my understanding.
EDIT: Well, she's not killing them. She just keeps the bodies that she finds. It's gross but as long as SHE didn't kill them, then I wouldn't take it so seriously.