I have been contemplating whether or not DJH would intentionally kill Jacob or not, based on his M.O. with JS and possibly the Paynesville incidents. None of the other attacks lead me to believe he would kill Jacob just to kill him. Then I remembered DR's statement about seeing a woman, or possibly a child covering their eyes in that car that went through his driveway the night of Jacob's abduction. If that was Jacob, and the perp had him cover his eyes, I would think his intention was to release him the same way JS was released. He probably needed to remove his mask to drive, and wanted Jacob to cover his eyes so that he didn't see his face. If he never intended to release Jacob, I can't imagine he'd care about Jacob seeing his face or not.
Did Jacob see him? Did Jacob fight back? Did the perp become paranoid after hearing what I'm sure was a lot of activity on his police scanner?
I don't believe Jacob's death was premeditated. I think something scared the perp, or Jacob fought back or tried escaping and he hurt him.
Just my humble opinion.