He may have perfected the hostage, live in thing later, but as far as proclivities go, I would think pedophiles always have that urge. He could have done very bad things at a younger age.
I wonder what Devil's story was going to be to neighbors and such--Shawn no longer living there (if he disposed of him) and Ben now living there. What story could possibly be believable?
I wonder how many other kids he victimized?