I've thought there is more to the story than what has come out so far.
If he wanted to kidnap Jayme so badly, he could have easily snatched her when she got off the bus..going to her home and murdering her parents just to get her seems like too much of a hassle on his part. The area from what I can see is VERY rural, he could have easily when she was walking home from school, grabbed her and no one would have known a thing