It is also still possible that she fell or tripped while jogging, injuring her head, and causing an accidental death.
The real tip-off is going to be whether or not they can figure out if anything happened to her neck with broken bones indicating some sort of choking or strangulation. Clothing has not indicated any sort of knife wound, stabbing, or heavy bleeding.
This would make sense if she had been found on or near the jogging path. She was found way off the path, near the road that separates the park from the residential area. She couldn't have fallen, hit her head hard enough to cause a skull fracture and then dragged herself that far only to collapse and die. Why drag yourself into the woods instead of down the path where there would be a better chance you would be found?
That fracture may or may not be associated with her murder. Somebody may have stepped on her partially or completely decomposed head as they walked on that slope and not even realized what they'd stepped on, just kept walking. Lots of things go "crunch" in the woods, right? If an adult foot came down on a thin part of the skull, such as the temple, it could easily create a fracture, even if the skull were covered with debris and laying on top of fairly soft soil. As time passed, that skull was bound to become more brittle and even an animal, such as a large dog, could create a fracture line by gnawing on it. Just the same, my guess at this point would be the same as yours -- she got clobbered.