That makes sense. But I still wonder why he didn't kill Shasta. Obviously, keeping her alive was a liability for him.
The man may have wanted to get caught. On his website, some of his demented ramblings suggest that he was disappointed when his crimes went unnsolved and he remained at large to do whatever. If that is the case, then Shasta would be a witness that could link him to whatever happened. Tell me, if he so wanted to escape detection, why did he go into a Denny's in Cour D'Alene, Idaho, near where the kidnapping took place and Shasta's picture had been plastered all over that area?
I read something on one of these threads, something he wrote on his blog about longing for companionship. My thought has been that he kept the girl as a companion. Being female, he was not sexually attracted to her. She was an obedient companion to keep him from being lonely. He has huge mother issues too.