On Easter Sunday, 2008, a detective repeatedly struck a plastic dummy doused in blood in an experiment part-way through the trial of a teenager, 16, charged with the shocking stabbing murder of a girl, 15, on the Central Coast.
The girl was stabbed 48 times in a frenzied attack only seconds after she stepped off a school bus and began to walk home. It was July 19, 2005, the first day of the third school term.
The killer, now 27, cannot be identified because he was 16 at the time, but is known as "DL".
Three psychiatrists who examined him found he was suffering from an anxiety attack, a psychosis, the early stages of schizophrenia or had signs of autism.
In 2008, a jury found him guilty of murder.
Justice Robert Hulme sentenced him to 22 years in jail, with a minimum sentence of 17 years. He is eligible for release in July 2022.
"Because of my view as to his mental state at the time, I am not satisfied that the prisoner's intention was to kill," Justice Hulme said.
The teenager's parents did not accept their son was a killer, and in 2008 vowed to fight for his release from jail.
"We're going to fight it with every breath in our body and we would not be doing that if we thought our son was guilty," the teenager's mother said.
The jury never got to hear the results of the detective's unorthodox experiment, but it was told of his expertise in "bloodstain pattern interpretation", and his views about blood found on the teenager's clothes that pointed to the teen's guilt.
In a judgment on Thursday, almost nine years to the day since the experiment, three judges of the NSW Court of Criminal Appeal ruled that, while much of the detective's evidence was misleading or incorrect, and almost certainly influenced the jury's guilty verdict, the murderer's appeal against his conviction "must be dismissed".
The victim's identification of the teenager as she lay dying in the car park of Forresters Beach Resort, after specifically ruling out another teenage boy as her killer, was "very powerful evidence" of the teenager's guilt, Justices Mark Leeming, Stephen Rothman and Helen Wilson found.
The court found a critical, unchallenged aspect of the detective's evidence was damning of the teenager.
The victim's blood was on clothes found at his house after police arrived to arrest him hours after the stabbing, which prompted a short chase as the teenager tried to run away.
The detective's experiment in court meant there was a risk the teenager was denied procedural fairness, but "this is not a case where the trial miscarried in such a way that it is not possible to assess" the strength of the case, the appeal court judges found on Thursday.
The appeal judges heard that, in the final 10 minutes of her life, the victim was repeatedly questioned about who stabbed her.
What she said that day kept her murderer in jail more than a decade later.
Four times the girl, who cannot be identified apart from the name Tania, named her killer as "D, year 10", and named a high school.
As she bled from 48 stab wounds to her head, neck, arms, legs, chest and back, and deteriorated in 10 minutes from being "completely awake", to unconscious, and then not breathing and with no pulse by the time ambulances arrived, Tania ruled out another named teenage boy as her attacker.
Four witnesses, who were with Tania as she lay dying, gave consistent accounts of what happened that day, had no motive to lie and their evidence was powerful, the appeal court found.
"Although the dying declarations could not be tested, they were in the circumstances of this trial very powerful evidence identifying DL as the assailant. Their force is not undercut by the submissions advanced by DL on appeal," the judges found.
DL's appeal for a possible fresh trial failed even though the court found most of the detective's evidence about bloodstain interpretation of the killer's clothes was "misleading or incorrect", had at least the risk of denying procedural fairness to the teenager's defence case, and contributed to the jury finding him guilty within 90 minutes.
The appeal heard the detective gave evidence about the bloodstains in the 2008 trial without knowing the blood was not just from the victim, but from the victim and the killer after DL cut his hand. This affected one section of his evidence.
The appeal judges rejected the argument that the prosecutor prejudiced the jury with a closing address questioning the defence case that the teenager confronted the killer and went for help.
"Why didn't he get help at reception? At the shops? From the passing cars on The Entrance Road?" the Crown put to the jury in the 2008 trial.
The trial heard evidence the teenager went to a house with a bleeding hand, obtained a Band Aid from a woman and told her he fell over a rock.
He told his mother he cut his hand on rose bushes and she took him to the doctor where his hand was stitched. He told the doctor he cut his hand on barbed wire.
"At no time did the jury hear evidence of any account by DL that he sought to prevent some other assailant from striking the victim. DL did not give evidence at the trial," the appeal judges noted.
"The prosecutor was highlighting the implausibility of a defence case consistent with innocence by exposing its inconsistency with what the Crown had demonstrated DL had in fact done later that afternoon."
There was no motive for the brutal killing.
In their decision on Thursday the appeal court judges accepted there were grounds for appeal based on the detective's incorrect evidence, and despite the "extreme delay".
The court acknowledged the impact of the lengthy delay of years between the defence's notification of a likely appeal, court hearings in 2016 and the final decision.
"It is not possible to assess the ongoing distress to the victim's family and friends by the undue prolongation of proceedings in this court, other than that it is undoubtedly real," the judges said.