A leading defence lawyer says police have a duty of care to everyone, irrespective of what crime they have done.
Marie Dyhrberg told TVNZ1's Breakfast this morning police did not follow correct protocols in restraining Alo Ngata who died in custody.
On July 1 2018, Ngata was pulled out from the back of a police van at the Auckland City Custody Unit.
His wrists were cuffed behind his back, his ankles tied together, and his entire face covered by a tight, opaque fabric.
CCTV footage showed his head slumped forward and his body limp. Only his foot appeared to be twitching.
About 20 minutes later, face down and alone in his holding cell, Ngata’s heart stopped beating. He never regained consciousness.
Ngata had been taken into custody that day after an argument inside the Auckland central flat where he was staying with his girlfriend. Ngata ran out of the flat enraged and brutally attacked victim Mike Reilly. Ngata stomped on Mr Reilly’s head several times, leaving him in a life-threatening condition.
The autopsy of 29-year-old Ngata revealed that on the day of his death, he was likely suffering from excited delirium syndrome - a kind of psychosis resulting in extreme agitation and aggression. It can be triggered by drug use and mental health issues.
The sufferer experiences paranoia, panic, unexpected physical strength, and high body temperature.
Professor Jason Payne-James, a UK-based independent specialist in forensic medicine, told TVNZ1's Sunday that excited delirium syndrome is a serious medical emergency.
“As a medic I would say that without doubt, anybody with excited delirium syndrome is vulnerable, they are at risk of sudden death."
Police completed two internal investigations and concluded “no person is criminally culpable for Mr Ngata's death".
However, Ms Dyhrberg is calling for an independent public inquiry.
She told Breakfast police were appropriate in the force used up until the spit hood.
"I understand from report that it has already been assessed by internal police inquiry it [the spit hood] was not applied correctly because the spit hood went right up the face whereas it should only have been across the nose and the mouth," Ms Dyhrberg said.
"But what has to happen is once that spit hood is on then there has to be constant monitoring to ensure that at all times the person is able to breathe, that they are able to look after themselves in terms of not having their main systems shut down, and what I understand of course is he wasn't closely monitored at all times and in fact was left in a cell face down, still restrained.
"He could never have removed the spit hood himself if he was choking therefore he wasn't posing a risk but left unmonitored and that is in serious breach of all the rules."
Ms Dyhrberg also said medical attention should have been given to Ngata, who was bleeding after it's believed he hit his own head against the ground and a car.
She said given he was bleeding, pepper sprayed and Tasered, police should have instead used protective gear themselves to keep him from spitting and possibly infecting them.
Breakfast host John Campbell put to Ms Dyhrberg: Why is it important? Why are you speaking up for correct procedure here? Why does what happened to Alo Ngata matter?
Ms Dyhrberg says Ngata's death "matters for a couple of reasons".
"One is, we want to prevent further deaths where the protocol has not been applied properly, so prevention is very important.
"Also, the public must have confidence in the police that irrespective of what we have done, what somebody has done, not matter how egregious their conduct is, they are entitled to be properly cared for.
"The public need to have the confidence that the police will look after anybody no matter that they have done and that is what goes with their power - the responsibility that police at all times as best they can will look after the public irrespective of what they've done.
"You cannot judge someone and say 'well they've done something terrible, therefore they fall short of being properly protected by the police'. That would be such a terrible position for New Zealand as a very caring and law abiding state to be in. We just are not that sort of people."