I think one of the saddest points about this case is that there was enough evidence to create far more than reasonable doubt regarding the prosecution case in the case papers, from before the start of the trial.
So much of it, we did not know about until literally years afterwards (in Scotland, the accused/convicted person has no right to see his/her own case papers, and it is an offence for those papers to be shared with a third party. Further, if a third party should somehow obtain access to case papers, it is also an offence for that person to make those papers public, so you can have some idea of how difficult this case has been to highlight over the years!)
So, for example:
a number of male DNA profiles on the body, the clothing, and the crime scene. These are not just any old common or garden DNA samples, they are from semen and sperm heads - none of them Luke's
Saliva stains, blood and hair on the body, the clothing and the crime scene, all unidentified, none even attempted to be be claimed as "partial" matches to Luke
A number of males close to the investigation (not Luke or any of his family members) who either had no alibi for the pertinent time scale, or whose original lack of alibi was remedied by later testimony from other people close to the investigation, some with apparently vested interests in supplying such testimony
No time of death, nor any reliable evidence to support the "claimed" time of death, other than the contention of the SIO that this was the time.
The crime scene was bleached before sniffer dogs were brought in
The search area for the sniffer dogs was restricted to the areas leading towards where Luke Mitchell lived, to the exclusion of a number of areas which, it could be argued, should have been considered significant to the investigation - not that it mattered, since the scene had been bleached anyway!
The family search trio's account of their movements that evening, and their claimed reasons for going straight to the path to look for Jodi do not stand up to scrutiny - according to phone logs, etc, when compared to statements from the search trio and other members of Jodi's family, the search trio arrived at the start of the path before they actually set out to search, and, by their own admissions, they headed for an area they would not have expected Jodi to be that evening, having been told explicitly that she was expected to be in the opposite direction entirely, and an area which they tried to claim jodi was not allowed to use, and would not have used alone. (At the time they made these claims, they were of the opinion that Jodi had not been with Luke that night, so they had no reason to believe that, had she been on the path with someone, that someone was Luke Mitchell.
There are so many elements of "evidence" which were never used by the defence - it is really shocking when you see how much information never makes it before a jury - not just in this case, but in so many others as well.