Work and Income double killer Russell John Tully has lost an appeal against his conviction and sentence.
The Court of Appeal has dismissed Tully's challenge in a decision released this afternoon.
Tully is serving life imprisonment with a minimum non-parole period of 27 years for the 2014 Winz slayings.
Tully was found guilty in 2016 of storming the Ashburton Winz centre at 9.51am on September 1, 2014, and shooting dead receptionist Peggy Noble, 67, from point-blank range and shooting case manager Susan Leigh Cleveland, 55, three times as she pleaded for her life.
At his trial in February 2016, Tully represented himself after having dismissed seven lawyers previously.
He was excluded from the courtroom for much of the trial after persistently disrupting proceedings in an attempt to have the trial aborted.
Tully was found guilty of the murders of Noble and Cleveland, and the attempted murder of Adams.
He was also found guilty on two counts of unlawful possession of a firearm but acquitted on charges of attempting to murder Curtis and of laying a trap for his pursuers as he fled the scene.
The Court of Appeal judgment released today said it agreed [with the judgment] that there is an imperative need for community protection and that Tully's "sense of entitlement is likely to bring him into conflict with others and he is capable of being very dangerous."
It said because these characteristics are primarily the product of a personality disorder, there is no reason for optimism about rehabilitation.
"Mr Tully's intractable sense of grievance, which is evident in his every dealing with the Court, may well preclude treatment."
It said it agreed that Tully does not experience remorse.
"The only possible mitigating factor is his mental health," it said.
"We also accept that but for that illness Mr Tully might not have approached Winz or become as insistent as he did on receiving what he thought were his entitlements.
"Nonetheless, it was his narcissistic sense of entitlement rather than his delusional skin disorder that explained his animus toward Winz."
The NZ Herald reported that throughout his 2016 trial at the High Court in Christchurch, it was clear that Tully was preoccupied with what he felt was a debilitating skin condition – and that he used peroxide to treat it.
When one Ashburton Winz manager first met Tully in July 2014, he told her he had "some sort of skin-eating disorder" that he used peroxide to treat.
He became annoyed when Winz staff said they couldn't help him with cash to buy the bottles of hydrogen peroxide he tipped in his ear.
The Court of Appeal decision said his "planned, organised and purposeful behaviour which extended to disguising himself and making his escape" strongly indicates that he understood well what he was doing.
It added that it considered Tully "an intelligent man who behaved strategically throughout his trial, and this appeal" and that he exploited "his health complaints to escape accountability for his actions."