The 30-year-old died in a prison cell in February 2011 from a suspected drug overdose after arriving at Otago Corrections Facility near Milton with drugs concealed internally.
Coroner David Crerar released his findings today, recommending that the circumstances of Mr Davis' death should be investigated by the Health and Disability Commissioner and the Independent Police Conduct Authority.
Southern District Police today acknowledged the Coroner's findings, saying communication between police, Corrections and the prison had been improved.
Mr Crerar today described the actions of Corrections staff at the Milburn facility as "insufficient''.
"There is again a disturbing lack of the recording of any of the communication,'' he said. "If a Corrections Officer has concern about the health of a prisoner then this concern should be drawn specifically, and immediately, to the Health Centre in writing.''
Mr Crerar panned police for their initial handling of Mr Davis at the time of his arrest and during the subsequent investigation into his death. The inquiry was not "conducted in a timely manner'' and was "cursory'' and "flawed'', he found.
"Too often during the inquest hearing a witness would state that they could not recall a specific because the death was 'so long ago'. My inquiry has been hindered by the failure of the police to conduct the necessary (and prompt) enquiries into a death as they are required to do.
"The police were requested by me to conduct enquiries and were reminded of their obligations on many occasions.''
While the nurses who cared for Mr Davis at the prison were not provided with all the information they should have been, it "is not an excuse for nurses to fail in their duties to provide appropriate and necessary nursing care'', Mr Crerar said.
The cause of Mr Davis' death was established at a post-mortem and supported by ESR toxicology as "the ingestion of lethal amounts of diazepam and dihydrocodeine'' owing to the full pill bottle of diazepam and dihydrocodeine tablets and a ziplock bag containing cannabis leaf or bud and cannabis oil which the man smuggled into the jail and later consumed to conceal them.
Despite his criticisms, Mr Crerar said Mr Davis was the "person most responsible for the circumstances which led to his death'' and there was no evidence that he had the intention of taking his own life.
Police investigated the actions of officers involved in Mr Davis' handling and death.
The IPCA reviewed that investigation and found the issues identified during the inquest were "fully considered'' during the police investigation, and the IPCA did not consider there was a need for a new inquiry.
The Coroner said many lessons had been learnt by the death and recommended that:
- Corrections consider adopting similar procedures and protocols as those used by police when dealing with people suspected of carrying drugs by internal concealment.
- Police consider the establishment of a generic email address for its intelligence operations so intelligence advice provided is not delayed by the non-availabiliy of an individual email address.
The review was completed in February this year and found that the available evidence failed to meet the standards required by the Solicitor-General's Prosecution Guidelines and no charges against any individual should be laid in relation to the death.
Police said since this incident, they and Corrections have agreed to a process by which information requiring urgent action can be passed between Southern Police and the Otago Correctional Facility to ensure thorough and timely communication occurs about such matters in the future.
Prior to the the Coroner's findings being released, police conducted a review of the investigation, which was carried out by an officer from outside the district.
That review identified similar issues to those released in today's findings, which in addition to the work already under way with Corrections at a national level to improve information sharing, have already been addressed by the district, police said.
The Independent Police Conduct Authority has also advised police that it is satisfied with the review.
