I haven't commented on the Kahui case because, bluntly, I loathe the entire genre of crime d'jour reporting, and don't want to encourage it. But I do have to comment on the statements politicians have been making over the Kahui family's silence and refusal to speak with police. According to the Herald, Maori party co-leader Pita Sharples said that the police should bring people in for questioning, while NZ First's Ron Mark has issued a press statement calling for them to be arrested for obstruction of justice. These calls are dangerous and authoritarian, and, if acted upon, would grossly violate one of the fundamentals of the New Zealand justice system.
I'm not going to be popular for saying this, but I think people need to be reminded: in this country, you do not have to talk to the police. There is a right to silence, both legal and practical, and a right against self-incrimination. The police cannot arrest you simply for refusing to talk to them, and it is not a crime to do so. And if you are arrested, you still do not have to talk to them, just as you do not have to give evidence at trial if charged. These rights are fundamental to the New Zealand justice system (and to those across the civilised world), and they exist for very good reasons - chief among which are protecting people from abuses of power and stopping the police from compelling testimony and forcing "confessions".
It is frustrating when people do not come forward with evidence about a crime, and politicians naturally want to be seen to be "doing something" about such a high profile case. But the best thing they can do is shut the fuck up and let the police get on with their work. We should not ignore one of the fundamental safeguards of our justice system simply to relieve politician's and the public's moral panic.