Yes I agree Dr S. We really have no idea how Samantha was killed. Was it a crossbow bolt or was she hit by a car? We don't know anything yet. There are so many known unknowns and probably a few unknown unknowns, at least for the general public.
We don't actually know what he was doing at Mt Clear at 8am on that Sunday morning... He was living at Scotsburn, down the track a bit...or how he got there, and left there. Some vehicle of some sort seems logical, but who knows? ...
The other factor in common Samantha Murphy had with Jill Meagher, and Eurydice Dixon, and Aiia was, these ladies, like Samantha were Doing Things Jill was walking home from a work party, Eurydice was walking home from performing at her gig in town, Aiia was on the tram home from a concert she'd attended. ALL NORMAL THINGS TO DO. Samantha , going for her normal training run in the cool of the morning, NORMAL THING TO DO.
Their murderers...on the other hand , were drifters, meanderers, wandering about looking for strife, concocting nonsense in their heads and seeking a target to enact their vicious fantasies out on... Jaymes Todd had been drearily riding back and forth on the Kensington line, Bayley was dawdling about Sydney road because his girlfriend kicked him out, Codey Hermman, what can one say, he didn't know where he was or what he was doing, apparently.
What was Stephenson doing hanging about the forest that Sunday morning so early? he ain't no runner, no marathoner... what was he doing there? All these killers tried to distance themselves from their act, ...they knew what they were doing .