The country's top detective and architect of a controversial police interviewing technique has announced he is leaving the police force.
Detective Superintendent Tom Fitzgerald, the head of the police national crime group and director of the Criminal Investigation Branch, has been involved with some of the country's most high-profile murder cases.
These included the conviction of Scott Watson for murdering Olivia Hope and Ben Smart in the Marlborough Sounds in 1998.
On Friday morning, Fitzgerald, 58, confirmed to colleagues he was retiring, though he would lead project work with police in the future, as well as taking up consulting opportunities outside of police.
In the past year, Fitzgerald has come under considerable scrutiny for the use of the Complex Investigation Phased Engagement Model (CIPEM) interviewing technique, which he authored, but Fitzgerald said his retirement is completely unrelated to this.
The method, which aims to create a relaxed, non-confrontational interviewing atmosphere during police investigations into cases that have proved hard to solve, was used during interviews in the Lois Tolley murder investigation.
One of those interviews resulted in a confession from a suspect, which was later ruled inadmissible by a High Court judge.
The judge said two CIPEM-trained detectives had misled the man, and "manipulated" him to make a confession that was "very flawed" and "not credible".
While Fitzgerald did not interview the suspect, he was watching proceedings from an adjoining room and giving the interviewing officers advice.
The case against all three men charged with the murder subsequently collapsed, with all charges being withdrawn.
Fitzgerald claimed the fault lay with the interviewing officers, and not the CIPEM technique, which he argued aimed to treat suspects with respect and empathy.
Fitzgerald told Stuff his retirement had absolutely nothing to do with scrutiny and criticisms of CIPEM, now re-named Peace Plus, and he was proud of what they had put in place.
The technique has been used by police since 2018 in five cases, but its existence was only made public this year as part of a Stuff investigation.
Fitzgerald had earlier stated he was stepping back from a hands-on role with the interviewing method.
His retirement comes two weeks after the resignation of another senior member of the national crime group, Detective Senior Sergeant Maania Piahana, who was part of the CIPEM interviewing team and oversaw cold cases.
Fitzgerald joined the CIB in 1993 and has been involved in over 100 homicide investigations, and was made an Officer of the New Zealand Order of Merit in 2017 for his services to police and the community.
He said the decision to retire had been something he had thought about for some time, and the timing was right.
Fitzgerald paid tribute to his family who had supported him throughout his 31-year police career.
"I've ruined numerous holidays, numerous nights out, I've commuted, I've lived overseas, and they love the fact that we serve the community and been nothing but positive."
As a key officer in the investigation into the disappearance of Olivia Hope and Ben Smart in 1998, Fitzgerald interviewed the leading suspect, Scott Watson, and the most crucial witness, Guy Wallace, as well as jailhouse witnesses police used in the case.
He arrested Watson in June 1998, and claimed Watson said, "about time", when confronted - something Watson has always denied.
He also led the investigation into the rape and murder of Christchurch woman Emma Agnew, with Liam Reid eventually being convicted of the crimes.
This story originally appeared on Stuff.