Significant and ongoing failures in the way police handled missing person files have been highlighted in a Coronial inquest into the death of Glen Collins. 

Collins was repeatedly stabbed by David Charles Gilchrist in the back, neck, and upper body, at the Upper Hutt home of his partner, Lisa Gosper, in an unprovoked attack on September 20, 2018. 

Despite the attempts of neighbours to save the 45-year-old father-of-two, he died at the scene. 

Gilchrist, who had a history of psychotic illness and violent behaviour sometimes heightened by illicit drug use, was charged with Collins' murder but found not guilty by way of insanity in March 2019. 

Coroner Brigitte Windley acknowledged the horrific nature of Collins' death as the hearing got underway on Monday. 

Windley said the inquest would bring a range of emotions to the forefront of the minds of those involved but it was not about blame or findings of liability. 

The hearing was about establishing the facts and accountability to reduce the chances similar circumstances could result in another family having to endure such an ordeal, she said. 

An officer involved in the case said Gilchrist, who was subject to a compulsory treatment order in the community, had been reported missing to Whangarei police by the Northland District Health Board on August 30. 

Gilchrist, who had not been taking his medication and was deemed high risk by the health board, had an extensive police history that included serious assaults using weapons. 

He had been stopped the night before the murder and arrested for three petrol drive-offs, between August 26 and September 7 while travelling south, but was released on bail. 

The officer said while the constable who pulled Gilchrist over could have held him under the Mental Health Act, he didn't present as having a mental disorder at the time. 

He said the officer assigned the missing person file was on leave, the file had not been reassigned and a risk assessment of Gilchrist had not been carried out. 

Similar concerns were highlighted in 2016 "without the tragic consequences". 

Different police districts had discretion how they approached the issues, so there was no consistent method to record a risk assessment being conducted or checklist to determine the appropriate response, he said. 

The officer, who can't be identified, said while a doctor described Gilchrist as "high risk" in a medical context, in a police context it may have not have been an adequate description. 

Gilchrist had also been stopped for speeding in Wellington on September 8, but the vehicle he was driving was not flagged as being used by a missing person and a flag detailing his violent history had also not been entered into the system. 

There had been insufficient liaison with the health board after Gilchrist had been reported missing, and a number of enquiries that may have led to him being located earlier were not considered or completed. 

The murder 

Gilchrist had began working with Collins on September 10 and had recently moved in with him and his flatmate after they discovered he was living in his car. 

Collins had been dropped off at his partner's house by Gilchrist who then returned home and drank two beers before returning to the house with a stainless steel knife with a 20cm blade. 

As the men walked towards the garage Gilchrist, who had formed the belief Collins was evil and had control over him, plunged the knife into his back without warning. 

At one point a 14cm piece of the blade broke off imbedded in Collins' spine but it didn't deter Gilchrist, who continued to stab him. 

Collin yelled for help during the sustained attack and his screams attracted the attention of the neighbours who arrived to investigate what was happening. 

Gilchrist, however told them "no, it's all good, it's just a dummy. It's just a joke'', before running back to his car. 

He returned to Collins' house where he showered, washing the blood from his body, shaved his moustache off and threw the knife into the Hutt River. 

Police arrested Gilchrist at the address. 

In March 2019 in the High Court at Wellington Justice Peter Churchman declared the 36-year-old a special patient. 

Gilchrist, who had been jailed in the United Kingdon between 2005 and 2009 for two armed robberies fuelled by his cocaine addiction, would continue to be held indefinitely or until a direction is given by the Minister of Health that he be reclassified or discharged, Churchman said. 

The inquest continues.