The Herald over the weekend had a story about what appears to be an appalling miscarriage of justice. Back in 1994, 17-year-old gang associate called Teina Pora was arrested and convicted of a particularly nasty rape and murder, after making multiple, inconsistent, and in some cases provably false "confessions". But in 1996, DNA evidence showed that serial rapist Malcolm Rewa had in fact committed the crime. Rewa was tried twice, but acquitted, largely because the police had already convicted someone else of the crime. As for Pora, he got a retrial, which convicted him because of Rewa's acquittal. He's been in jail now for almost twenty years, for a crime which it appears he did not commit (and of course can't be granted parole because he refuses to admit guilt).
The police, of course, don't want to know. They've got their man (well, a man), and reopening the case would be messy and ruin the stats (not to mention result in embarrassing questions about how they got a teenager to confess to something he didn't do). As with Arthur Allen Thomas, police prestige is apparently more important to them than justice. And then they wonder why people don't trust them...
Pora has applied for a retrial under the prerogative of mercy. Hopefully he'll get it. But is a bit haphazard. In the UK, there is a specialist body, the Criminal Cases Review Commission, specifically to assess possible miscarriages of justice. It sounds like we need one of those here as well.