A controversial police interrogation method that was implicated in a false confession is under fire from human rights lawyers, criminologists and psychologists.
Earlier this month, Crown Law and police lost their legal battle to keep secret the method used in the Lois Tolley murder case, which collapsed late last year.
The case unravelled against Mr X (one of three men charged over the crime), after his so-called "confession" turned out to be a fabrication, obtained by dubious means.
Those dubious means were finally revealed after the news organisation Stuff took legal action to get suppressions lifted on a High Court judgment.
In that judgment, Justice Simon France was scathing of police procedure in this case:
"A persistent denial was persistently rejected.
"A man with an unusual and, to my eye, confused way of thinking has been further confused by an unfair interview process, which leaves him believing he has done the one thing most against his beliefs - namely implicating others, and particularly a person to whom he feels a very close attachment and duty."
Plucked from his prison cell with no warning to be taken away by police and plied with McDonalds, Mr X appeared confused about what was going on - and that was intentional.
The Complex Investigation Phased Engagement Model - developed by national crime group boss Detective Superintendent Tom Fitzgerald - was likened by the judge to a "cosy fireside chat".
There was no note-taking, no table between them, it was just a couple of mates having a yarn.
Transcripts reveal how one of the detectives quickly rattled off his rights to Mr X in an off-hand way ("We're talking to lots of people, we may as well do this with you"), before quickly asking "How's that McChicken?".
Over the next few hours, the tone shifts.
Mr X is repeatedly exhorted to be "a hero" like his father and make his children proud.
He has already said "too much" and got his friends in trouble, according to the detectives.
"Now it's time for you to tell me, okay… why it's an accident. Okay you need to start helping your mates here, look after the bros. Okay you're the only one that can do that before somebody else says something else."
Mr X is led to believe that he himself is now at risk, and only the police can protect him now - but the window is closing:
Detective: Listen to me. Cos we gotta go soon.
Mr X: Yeah.
Detective: So this one day, this opportunity that you've had today
Mr X: Yeah
Detective: That I know you appreciate don't you. We've put you first. Everything we have done, today has been about you
Mr X: Yeah nah thanks bro.
Robert Lithgow, QC who represented Mr X, told RNZ there was nothing novel or problematic with a "cosy fireside chat" type interrogation.
"However when it is overdone to give an entirely false sense of fake mateyness coupled with not listening to what the suspect says and repetitive endorsement and insistence that they 'know' the true story (which they did not) it can lead to an entirely artificial narrative."
So why would someone confess to doing something of which they are innocent?
False confession expert Dr Andrew Evelo from Waikato University's psychology department said people being tortured might confess to anything just to make it stop.
However, psychological pressure could be equally compelling.
"People falsely confess for multiple different reasons, including because they want the interview to end, or they may believe they're implicating other people, or they may have come to believe they were involved when they weren't."
In interviewing Mr X in relation to Lois Tolley's death, the officers repeatedly suggested it was probably an "accident" and people would understand that kind of thing happening.
The method refers to this as "version challenge", offering an alternative explanation.
"Research shows that minimising - or giving people an 'out' - can make the innocent more likely to falsely confess," Dr Evelo said.
Canterbury University sociologist Jarrod Gilbert said it was "a tricky balance" for police because the public would expect them to use various techniques to elicit the truth.
Occasionally, these techniques could involve an element of subterfuge - but it was important for police to keep "an open mind", he said.
"There's a risk they can get confirmation bias so they only really hear what they want to hear and ignore evidence to the contrary, because once you get into that, once you become absolutely focused, it can send you down the wrong track.
"It can send you down a dangerous track."
It was very hard to undo a confession, even a false confession that conflicts with the facts, he said.
"Internationally, one in three convictions overturned due to DNA evidence involved false confessions or damaging testimony by the accused."
No-one from police was available for interview.
However, in a written statement, Acting Assistant Commissioner Dave Lynch said the sole objective of any police interview is to obtain a truthful and accurate version of events.
"In respect of the case to which you refer, Police recognises that there were recording practices that could have been done better."
The internationally respected evidential interviewing expert Dr Mary Schollum had reviewed the Complex Investgation Phased Engagement Model - now renamed PEACE Plus (Preparation and Planning, Engage and Explain, Account, Clarification, Challenge, Closure and Evaluation) - and found it conformed with international best practice, he said.
She had made some recommendations regarding training and was helping police draft a new training manual, he said.
However, human rights lawyer Michael Bott remained skeptical.
"An 'ends justifies the means' approach in relation to an interview technique which has inherent concerns about reliability, is not salved by the fact that some so-called independent person of police has given it the green light."
The police have commissioned Aaron Perkins QC to do an independent review of "aspects" of the Tolley inquiry by police.
Acting Assistant Commissioner Dave Lynch said he was not in a position to give a time-frame for this or comment further at this time.
Meanwhile, more than five years after her brutal murder, Lois Tolley's family is still waiting for justice, with no-one currently facing charges.
