Steven to become a murderer??

[Perdita]

This is what annoys me about EE. They never delve into the past of their psychos. If they did it would give the characters more depth and make them more interesting, I think.. Stella... a wasted opportunity.. and now Steven too!

Yes, I agree, they never really explained Stella's reasons for being so horrible, other than she had problems herself in her childhood (unless I missed it).