The police won't be telling us everything. We don't know what new info they have collected now seven months on..
It's not enough just to prove that the accused and Samantha were in the same place at the same time.
They need to also prove (beyond reasonable doubt) that nobody else was there.
Questions, how can they do that? Just because no other phone pinged?
Someone else could have been there but didn't carry a phone
They need to prove intent.
This requires a motive, or other explanation (beyond reasonable doubt) which proves the accused acted deliberately or with the knowledge that his actions were likely to cause Samantha's death.
Again, how can they do this without an eyewitness or physical evidence or a confession?
They need to prove that the accused actions did in fact cause Samantha's death, and that she did not die from other causes.
Again, how do you do that without a body?
(Defence: yeah, I came across her body, she was already dead, I panicked and left. Someone else must have moved her body).
This is what will be playing out ...
There are quite a few folks currently serving life, never to be released, in prisons in all states of AU, Bradley Murphy, for one, who would entirely agree with your reasoning, as would Keli Lane. Keli's convoluted response to claims she murdered her baby daughter rest on no eye witness, no body, no confession....
Chris Dawson has spent about 3 million dollars, and a brothers reputation on positing the exact same argument, how could he be guilty with no eye witness, no body, huh? And so on, there they sit, in prison for life. no parole. Mainly because circumstantial evidence is not in any sense second class evidence but carries as much weight as physical evidence in court room.
In this instance, and it is unusual, but that does not relegate the claim to the backwoods, VICPOL claim, without a coroner seeing the body, without a confession, without a motive, without a background of agitation and conflict, that Stephenson murdered Mrs Murphy, at a concise place, at a concise time, alone, and with intent ( he 'attacked her ' )..
It has all been played out before, probably will be again , VICPOL has some evidence that clearly points to Mrs Murphy being murdered by Stephenson, otherwise the Dept of Public Prosecution would not proceed with the charge of murder. There has been no resiling of this charge, no evidence of horsetrading to get more info from Stephenson, VICPOL appear to be supremely equipped with enough stuff to march on without any input from Stephenson, at all . Not a word .
VICPOL, and the DPP, and the judge, and the jury are not involved or interested in motive. Motive is a concept that the court does not need to make an adjudication. Motive is nice to talk about, it gives some sort of meaning to horrible happenings, but it is a slippery concept, only the killer knows the motive, and even that is not set in concrete, some have no idea themselves why they kill. Of course, after lots of psychotherapy and truth serums and stuff like that, a motive can slowly emerge, maybe, or one that the killer can accept of himself, perhaps.... but generally, the 'motive' has no bearing on the actual victim's entity...