Mrs. DeBoer did not walk a mile and a half to the culvert, climb into it to commit suicide or die of natural causes.
She was murdered and her body was left there. Of this I am 100% certain.
As an aside but something that may be important one day to someone:
My very brilliant, very beautiful, step-daughter - an emergency room physician and infectious disease specialist - sat in her unlocked car at 3pm after a hair appointment, oblivious to everything around her as she fiddled with her dang phone. Some predator came from nowhere and got into the passenger seat of her car. He tried to grab her but she managed to escape his grip, get out of the car and scream loud enough to draw attention and he fled. It could have been a horror story. I wanted to shake her for being so foolish and risking her life sitting in an unlocked car, fooling around with a stupid phone and being unaware of her surroundings!
Mrs. DeBoer was also brilliant and beautiful, may have been distracted with that dang phone and unbeknownst to her, was being watched by a predator or predators. They look for vulnerable victims and women, alone and staring at a phone screen, texting with both thumbs is as vulnerable as a predator needs for a successful attack.
Please - don't make yourselves easy pickings. You never know who is watching your every move. Get in the car and drive away, don't sit there with a bullseye on you.