Planning an insanity defense. He's possibly been planning it for some time now, knowing he would eventually be caught. "Voices" from God, mind control, etc.,
weird religious ramblings. He might be trying to obtain a diagnosis of schizophrenia to help him escape a life sentence in prison. He may figure that incarceration in a state mental facility will be less painful and easier to take.
This guy is evil, that's certain. But he may also be very, very clever and not at all insane, at least according to the legal definition. I would expect the trial to be a circus, which will take years to conclude and cost the taxpayers millions of dollars. I can't imagine the additional pain Jaycee and the two children will have to suffer if they're called to testify.
In olden times, a man like this would be taken care of swiftly and never heard from again.