I hope LE is able to establish a reliable time of death. Something about this crime scene seems a little off to me. I'm wondering if maybe she was being held somewhere until the heat got turned up too high.
It seems hard to believe that she could've been lying in that culvert for 6 full days without being noticed by passing motorists, cyclists, or joggers. Due to the ongoing search efforts, I would think that hundreds of both volunteer searchers and law enforcement personnel would've turned on to this main road many times during the last week, right at that intersection. Yes, there is a culvert there, but it doesn't look like a very deep culvert. Not to mention, this intersection is located very near a highly populated residential area. All of that traffic and nobody bothered to glance down into the culvert for over a week ?
If she got into a vehicle that morning with someone she knew, it is totally feasible that this same person could actually live right there in the neighborhood, or closeby, and most likely would.
There was a case here on Websleuths last year where a guy that worked at a legal massage business abducted and held a fellow coworker for well over a week inside his apartment. It was only after the police began coming around to question him that he murdered her and dumped her body in a wooded field. Apparently he tied her up, tortured her, and sexually assaulted her for about 10 days. None of the neighbors living in adjoining apartments heard or saw a thing. When she was found, it was established that she had only been dead for a couple of days, although she had vanished two weeks prior to being located.
I would think that in almost any case where an active search is going on for someone, all of the parties involved would be hyper-vigilant while driving up and down the roads searching for the missing person. This would include family members, volunteers, law enforcement, and the surrounding residents who were aware of the search. An area a little over a mile away in a virtual straight line from where her car was found, with a high volume of daily traffic, next to a busy intersection , was completely overlooked ?? It doesn't add up.
Map here:
https://www.google.com/maps/d/viewer?mid=zAAmDUXJe_aE.knlZzA2tpxDE