He is a monster, it takes a good 3 to 5 minutes to strangle someone to death by your hands. Tons of experts, people with medical backgrounds have been interviewed over this case about how long it takes to strangle someone to death and its a long time, its not like the movies. There is ample time to come to your senses and stop choking them, where as he kept going for multiple minutes until she was dead. Also, it was stated by Gabby's stepfather on Dr.phil that where they found the body, there was evidence that a camp had taken place. There was a noticeable spot on the ground where you could tell a fire was and there was tent holes in the ground.
He was always facing murder one, not murder two, because of the fact he killed her via manual strangulation/throttling and having ample time to stop himself over the minutes of choking the life out of her. If you're choking someone for minutes until they're dead, that is killing with intent, not accidental, etc.