Multiple failings by police enabled two officers to lie and provide false evidence in the investigation of a central Otago car crash which was wrongly pinned on a teenager, the police watch dog has found.

The report from the Independent Police Conduct Authority, released today, slated the police handling of the investigation into a July 2005 motor vehicle crash in Alexandra.

It detailed how sloppy police work eventually resulted in the wrongful conviction of 17-year-old Shane Cribb, and also prompted an apology from Southern District Police regarding its conduct

The report into the crash, between Mr Cribb's vehicle and Senior Constable Neil Ford in an unmarked police ute, comes years after Mr Cribb's careless driving charge in relation to the incident was dismissed and Ford was found guilty of perjury in the case.


A second police officer, Constable Dairne Cassidy, who was appointed to investigate the crash, was also convicted of misleading the court over Mr Cribb's conviction in 2006.

Today's report also acknowledged the work of Stephen Potter, the father of Mr Cribb's girlfriend at the time of the crash, in uncovering faults in the investigation.

The IPCA concluded that police failed to critically examine Ford's account of the crash and the physical evidence; comply with policy and best practice; provide adequate supervision and leadership and remedy the deficiencies that had been identified in the investigation and address Stephen Potter's concerns about the crash investigation in an appropriate way or in a timely manner.

Authority chairman Judge Sir David Carruthers said a lack of adequate supervision and failure to critically examine evidence and remedy problems were identified in the investigation.

"These inactions resulted in police not uncovering the truth about the crash for over two years, causing much undue stress to Mr Cribb and his supporters. Furthermore, the mishandling of the crash investigation also greatly damaged the reputation of Southern District police," he said.

Southern District commander Superintendent Andrew Coster said police failures had led to serious consequences for Mr Cribb.

"[He] was wrongly blamed and then convicted for causing the crash. Police let Mr Cribb down badly, and to go some way to resolving this, we have apologised to him and provided compensation.

"Police accept that without the persistence of those members of the public who supported Mr Cribb, police would not have reinvestigated the case to uncover the truth about how the crash occurred," he said.

Both Mr Coster and Sir David agreed a number of improvements had been made within the police force since then.

The authority also acknowledged its own processes had contributed to the report's delay, which comes nearly nine years since Mr Cribb was involved in the crash, and almost six since his conviction was dismissed.