Disgraced former detectives Roger Rogerson and Glen McNamara are set to die in jail after losing their appeals over the cold-blooded execution of a Sydney student and drug dealer.
"The case relied upon by Rogerson was completely lacking in credibility and did not raise any doubt about his guilt," the NSW Court of Criminal Appeal concluded.
The three judges on Friday also found no merit in McNamara's appeal against his conviction and sentence.
While no one at their trial contended either man was "a criminal genius", the judges observed they may well have succeeded in their venture but for unforeseen circumstances.
Rogerson, 80, and McNamara, 62, were jailed for life in 2016 after being convicted of murdering Jamie Gao in May 2014.
They also were jailed for stealing 2.78 kilograms of methamphetamine with a street value of up to $19 million from the 20-year-old student.
After a lengthy hearing in September, NSW Court of Appeal president, Justice Andrew Bell, and Justices Robert Allan Hulme and Robert Beech-Jones dismissed the appeals.
The Crown relied on 29 circumstances to prove its case that both men were part of a joint criminal enterprise to steal drugs from Mr Gao and kill him.
He was lured to a darkened storage shed in the city's south and shot dead, before Rogerson and McNamara attempted to cover their tracks by dumping his body at sea.
Both accused ran cut-throat defences at their trial, each arguing that the other had organised to meet Mr Gao at the storage unit and that it was the other who shot him.
The prosecutor had contended it didn't matter who pulled the trigger because jurors could convict them of murder on the basis of a joint criminal enterprise.
Rogerson's appeal grounds included a claim the verdicts were unreasonable and could not be supported having regard to the evidence.
Noting the Crown argued it was a carefully premeditated and serious crime, Rogerson's barrister submitted it was "inconceivable" that the experienced criminal investigator would not have thought through basic flaws such as bringing his own car to the crime scene.
The appeal court noted the trial prosecutor's response to the proposition that "if you were going to plan a murder, why do it there at Rent-a-Space with the CCTV?"
"The argument referred to three unexpected things occurring: the deceased's friends speaking to the police; the police having a lead to go and investigate at Rent-a-Space; and the body coming to the surface and being discovered.
"This argument that a man as experienced and astute as Rogerson would not have been so careless fails equally upon consideration of his own account."
While Rogerson had accepted during cross-examination that he was once a very experienced police officer, he protested that as at May 2014 he had started to think he was naive.
"I have got to 75 years of age and I am not the man I used to be," he testified.
The three judges found the case for Rogerson was substantially damaged by matters adverse to his credibility, including unlikely or "frankly absurd" explanations he gave.
McNamara's rejected grounds included a claim that the trial judge erred by not allowing him to detail his prior belief that Rogerson had murdered before and that McNamara, therefore, acted under duress.
McNamara claimed in one conversation Rogerson told him he had killed six people and in another that he had conspired to kill another.
This was said to have reinforced and strengthened the potency of Rogerson's alleged order to help him in the aftermath of the murder otherwise he and his family would be killed.
"In our opinion, the trial judge's decision to exclude the evidence of the two conversations was correct, as was his evaluation that the evidence sought to be adduced was of limited probative value."