It took the intervention of a citizen - ably and determinedly assisted by lawyers Jonathan Krebs and Ingrid Squire - nine years after Pora was convicted a second time. It took a further six years of work to clear him.
McKinnel's misgivings about the case came after witnessing as a junior detective heated debates between his seniors in the police bar.
After leaving the police, McKinnel used the same tools we all have - the Official Information Act and privacy laws - to investigate.
His young family and his business had to accommodate the long absences and the hit on income that resulted.
He made more than 50 round trips by car from his home in Hawkes Bay to Paremoremo to visit Pora, twice sued the police to release information, found police incompetence, hidden deals and new evidence.
McKinnel's work once again raises the question about whether our tightly proscribed system of appeals is adequate or whether an independent, publicly funded case review system as advocated a decade ago by former appeal court judge Sir Thomas Thorp, is a necessary additional safeguard.
Unsurprisingly, the Government says, no, the Opposition, yes.