i had a few thoughts this morning on this case and wanted to throw them out there... much is based on rumor which i know is not allowed here but my intent is not to spread these rumors... i have no inside information and have no relation to this case...
i thing the general opinion is this was carefully preplanned by the perp and that this victim was sexually assaulted, then carefully disposed of... i think that may not be the case here... i think she may not have been sexually assaulted (as planned) at all. if this opinion has been discussed here i have not seen it...
perp hits or otherwise abducts victim...
victim fights back once inside the truck and causes a serious neck injury to perp. causing massive blood loss, possible dizziness etc, and perp has to prematurely murder his victim at the abduction location...
perp returns to his house (body still in truck) to try to patch his wounds and stop the bleeding but needs immediate medical attention...
perp drives to another county to seek medical attention and hastefully disposes of bike/body along the way...
after being patched up, perp returns home...
then seeing the search effort is way more than he imagined, knowing he will be investigated because of his SO status, he starts to get spooked and comes up with the plan to dispose of his truck and comes up with the plan to dispose of it in the other direction (tx) and files to have his SO status lifted... etc...
again i do not know many of the details, but from what i have read, this sounds like a likely possibility...