Is anyone else thinking that maybe the (somewhat erratic and excitable) sheriff has this all wrong and there was no abduction? I'm imagining Mrs. Guthrie waking in the middle of the night, falling on the way to the bathroom, stumbling out the door (to get help? because she didn't recognize her own house?), walking down the driveway and disappearing into the brush and dying, perhaps farther away than where she is believed to be able to walk. So many times bodies are found in areas already searched thoroughly, so I'm not convinced that if she was within 100 yards of the house the searchers would have actually found her.
Anyway, at this point, knowing foreign DNA hasn't been found and that cameras haven't identified an intruder, this makes more sense to me than kidnapping an 84 year old woman in the middle of the night. And the ransom notes seem clearly ridiculous.