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Police have officially cleared themselves of any blame over their handling of the Kahui double murder investigation, insisting the decision to charge the twins' father was the right one.
The contentious findings come four months after a High Court jury threw out the police case against 23-year-old Chris
Kahui, who went on trial this year for the murder of his twin boys, Chris and Cru.
Despite the acquittal, and the fact no one else is likely to be held accountable for the deaths, the formal evaluation of the police case - which was branded a "disaster" by Kahui's lawyer Lorraine Smith - makes few recommendations.
The report confirms new guidelines for dealing with infant homicides, including how to manage a crime scene, but there is no criticism of police for allowing members of the so-called "tight 12" - the extended Kahui family - to stonewall their inquiries.
All the report acknowledges is that "liaison with the family was always going to be difficult".
The debrief, carried out over a fortnight by Detective Superintendent Malcolm Burgess and released to the Herald on Sunday under the Official Information Act, also endorses the decision to charge Kahui, and not the twins' mother Macsyna King.
It says the decision was based on "medical evidence and the elimination of other possible suspects".
Throughout the trial, Smith maintained police ignored significant evidence against King, including the fact she lied about her whereabouts around the time the twins suffered their fatal injuries.
She has also raised issues over the delays in disclosing evidence during the lengthy investigation. That matter is now before the Independent Police Complaints Authority.
Chris and Cru were 3 months old when they were admitted to Auckland's Starship hospital with severe head injuries in June 2006.
Days later they died, sparking one of the most frustrating police investigations in recent history as family members closed ranks.
It took police four months to finally arrest Chris Kahui, who they argued was a stressed-out father who had "snapped", inflicting the fatal injuries in the minutes he was alone with the twins on the night of June 12, 2006.
The trial took six weeks as the prosecution called 65 witnesses.
The jury of seven men and five women had to consider 1933 pieces of paper evidence.
The defence painted 31-year-old King as a poor mother who drank heavily and smoked P while the twins were in her care.
Despite the jurors taking less than 10 minutes to acquit Kahui, inquiry head Detective Senior Sergeant John Tims maintained, based on the evidence, that police had charged the right person.
Others, like top Auckland lawyers Chris Comeskey and Barry Hart were not so sure, saying police should have looked more closely at King.
Maori leaders also waded into the debate with former MP John Tamihere one of the most vocal.
"My response to the acquittal... ranges between frustration at a police force that was too quick to charge Chris Kahui... and rage at the twins' family who closed ranks and refused to speak to detectives," he said.
In his findings, Superintendent Burgess found that "based on the medical evidence and the elimination of other possible suspects, Chris Kahui became the logical suspect and the focus of the police investigation".
"It is clear from an evaluation of the investigation that it was thoroughly completed with all likely lines of inquiry properly developed and taken to a logical conclusion," Superintendent Burgess found. "There was ample evidence for this matter to lead to a prosecution and upon which a jury might have convicted."
Tims did not return Herald on Sunday calls but Smith's co-counsel Michelle Wilkinson-Smith said it was no surprise police had taken the decision not "to hang anybody out to dry over this".
Police had put too much faith in evidence from one doctor who believed he had isolated the "most likely" timeframe of when the twins injuries had occurred.
However, when that evidence was later contradicted by another doctor, the whole of the Crown's case became flimsy, she said.
"Police will tell you they charged the right man. I am absolutely convinced they didn't."
Crown prosecutor Simon Moore rejected that claim, saying if the evidence had pointed toward King she would have been charged.
He admitted it was "unsatisfactory" that no one would pay for the deaths of the twins but said people should not lose sight of the fact the role of police and the Crown was to present the evidence to a jury so it could then make a determination.