Many things disturb me about VMs death. One thing is the lack of noise heard during the assault.
Let's say while on the blacktop of the road, the unsub used a garotte or rope to toss over the head to incapacitate VM. Unsub could just as easily use his arms to grab her around the neck and pull her to him. Perp scoops her tiny body and dashes into the woods. VM has the opportunity to kick her feet, scratch his arms and hands while he is attempting the strangulation. Now, his DNA is under her fingernails. She cannot scream because he is strangling her.
Then, Unsub does whatever occurred at the CS to cause her death. I agree with her likely being tied to the trees. Also, the unsub left a gruesome CS that was meant to shock and awe the first responders.
Another thing that has bothered me deeply is the horrific burning of Vanessa. Especially when used outdoors, a regular cigarette lighter produces a flame that is simply too small and would be time consuming to be an effective arsenal. Perhaps the Unsub used a flamethrower. Firefighters have access to them. The military has experience with them. Flamethrowers were used to melt the snow for JFKs inauguration. This vid shows how easy it is to make one at home or while sitting in the car ... waiting.
[video=youtube;H4GPXZazjHk]https://www.youtube.com/watch?v=H4GPXZazjHk[/video]