I too have been wondering why VS had no clothes on from the waist down.
It could be circumstantial evidence of a sexual assault.
Or, there could be other explanations, depending on what happened at teh actual crime scene.
Given the spot of blood on the back doorway of the car, I believe there was a lot more of it there before it was cleaned up. Therefore, I believe the facial injuries to VS occurred inside the car doorway as VS was being pulled out of the car by an enraged TLM.
I believe something happened to send TLM off into the rage that resulted in VS death. TLM has provided no testimony on "why" she decided to kill VS.
If true, there may have been blood all over the moulding and side of the car, and they may have had to clean up the evidence of blood from the side of the car before they continued to the car wash for a more thorough cleaning.
Perhaps they used VS pants to clean up some of the blood. They didn't exactly have the tools with them to thoroughly wash a car in that secluded location........so they used what they had on hand.
What was going through MR's mind...........I can't even fathom.
Why he wouldn't have thrown TLM to the ground and held her until LE arrived, I don't know. Maybe in her rage, even he was afraid of what she might do to him out on that secluded farm lane.
Perhaps she threatened him by saying.........you are in it as much as I am, or he completely lost his mind..........or he is simply a freak of nature who doesn't accept any responsibility for anything he does and justified his non action to himself by thinking he didn't actually do anything.
2) Or.....as some think.......he sexually assaulted VS and let TLM murder her.
If MR had a shred of common decency or humanity in him, I would think the first scenario would be the logical one.
JMO......................