Murders have a high clearance rate in New Zealand. Statistically, fewer than one in 10 goes unsolved. Perhaps because they are rare, many unsolved cases stick in the consciousness of the country. I suspect I could guess your age based on whether you know the names Jeanette and Harvey Crewe, Jennifer Beard, Kirsa Jensen or Kirsty Bentley.
Cold cases like these will likely never be solved. The one thing successful homicide inquiries tend to enjoy is a swift resolution. As more time passes the likelihood of charging an offender falls. Advances in science, particularly around DNA, have been able to assist with some cases; young Teresa Cormack was abducted and killed in 1987, but a conviction only gained in 2002. Cases like Chris Bush's, however, will require people to come forward. And here, at least, time can actually be of assistance. As time changes, so do attitudes and allegiances.
While two men robbed the pub, there's a fair chance a getaway driver waited outside. To have two or three criminals with the professionalism not to brag about a heist is rare; despite the obvious dangers, criminals often boast.
And in a case like this, the desire to talk has even greater motivation; the murder was almost certainly unplanned. The need to speak with somebody about what happened - the psychological desire to unload - would have created a relentless anxiety.
Even if the perpetrators' lips were tight, people close to the robbers may have noticed an influx of cash around that time or noticed them acting oddly when the case was discussed or in the media. For them, Labour weekend may bring up these old suspicions in the same ways it will flicker fading memories and sadness for the family and friends of Chris Bush.
Clues at the time of the killing were scant, and at one point a man falsely claiming knowledge of the case led the police up the garden path. It was one of numerous fruitless leads. But despite a lack of hard evidence, there is a belief among the cops they know the identity of the killer. I have no idea how credible their information is, but rumours swirl in the underworld around the same man.
But rumours are rumours and they could just as easily have all stemmed from one unreliable source and be completely false.
Something more solid is needed. For 29 long years, who killed Chris Bush has been a mystery. But who knows what another year might bring? Just because a case is cold doesn't mean it's closed.