What if you genuinely don't know who killed the child?

Few things are more disturbing than the violent death of a child, writes forensic scientist Ruben Miller. But believing someone knows something isn't the same as proving it.

Imagine three adults in a house where a young child has been killed. One knows exactly what happened, another suspects, but isn’t certain, and the third knows nothing. 

Police interview all three, but nobody provides an account that explains the child’s death. Investigators are frustrated and the public is outraged. The child’s family is left waiting for answers. 

Now imagine introducing a law that threatens those adults with ten years in prison unless they disclose what they know. It may sound pretty reasonable, particularly if we assume that somebody must be concealing the truth. But how do we establish which of the three actually has information to disclose? That’s the difficulty at the heart of National’s proposal to make withholding information a criminal offence in child murder investigations. 

Announced as a campaign pledge in October, the policy would create a new offence under the Crimes Act for failing to disclose information to police when a child aged 12 or under has been killed and adults were present at the time or leading up to the death. The proposed maximum sentence is ten years’ imprisonment. Justice minister Paul Goldsmith argues that the existing law allows perpetrators and their accomplices to avoid accountability by refusing to cooperate with police. He wants to place them in a position where remaining silent carries serious consequences. 

It’s an understandable objective – few things are more disturbing than the violent death of a child, especially when investigators believe people close to that child know what happened but refuse to say. Except that there is a difference between believing somebody knows something and proving that they do. 

The deaths of three-month-old twins Cris and Cru Kahui in 2006 demonstrate how complicated these investigations can become. Their father, Chris Kahui, was acquitted of murder in 2008, although a subsequent coronial finding, reached under a different standard of proof, concluded that the twins suffered their fatal injuries while in his sole care. To date, nobody has been convicted of their deaths. The case became synonymous with a supposed family-wide conspiracy of silence, a narrative that has endured for nearly two decades.

At a recent justice debate, defence barrister Marie Dyhrberg KC, who represented the twins’ mother, Macsyna King, challenged that characterisation. She said King had participated in 38 hours of police interviews before anyone was arrested, arguing that the familiar account of a family refusing to cooperate was misleading. I think this points to a danger of treating an unresolved murder as evidence that witnesses must be deliberately concealing the truth. 

More recently, in October 2023, two-year-old Baby Ru suffered fatal injuries at a Lower Hutt house where three adults were present. Three years later, nobody had been charged with his killing, despite an extensive police investigation. Police identified all three adults as persons of interest, and have said publicly that they collectively have information they haven’t provided, although Baby Ru's mother has publicly denied involvement and spoken about what she believes happened. 

It's almost precisely the situation National's proposed legislation is intended to address. Three adults, a dead child, and no prosecution. But even here, the difficulty isn't necessarily as simple as three people refusing to speak. In a situation like this, it's possible for one person to know exactly what happened, another to have incomplete information, and a third to know nothing about the violent act itself. 

Would threatening all three with imprisonment produce the truth, or only produce more statements? And how would police be able to tell one from the other? The right to silence exists partly because the criminal justice system recognises these difficulties. It helps protect individuals from being compelled to incriminate themselves and from the pressures that can arise when the State needs answers. It is not simply a convenient protection for guilty people. 

New Zealand law already has something to say about carers’ obligations in these cases. Section 195A of the Crimes Act already makes it an offence, in certain circumstances, to fail to protect a child or vulnerable adult from a known risk of serious harm. But that obligation concerns protecting a child from danger, rather than requiring people to provide information after a death. 

One challenging question with National’s new proposal is what happens when somebody suspected of involvement in the killing is compelled to speak. Would their answers be admissible in a subsequent murder prosecution? Would they receive protection against self-incrimination? And if they refuse to answer, how would prosecutors prove they possessed relevant information in the first place? The answers are important and the proposed legislation is yet to resolve them. 

There is also the problem of unreliable information. Imagine a woman living with a violent partner who suspects he may have killed a child but doesn't know exactly what happened. Faced with the possibility of ten years in prison, she might provide an account based on suspicion rather than knowledge. Alternatively, she might remain silent because she fears what

her partner will do if she speaks. Neither possibility necessarily brings investigators closer to the truth. 

Of course, the opposite concern is equally legitimate. If someone witnessed a child being killed and deliberately conceals the perpetrator's identity, there is a strong argument that society should not simply accept their refusal to assist. But that argument becomes less straightforward when the proposed offence extends beyond deliberate concealment to circumstances where knowledge and responsibility may be uncertain. 

On top of that, there is an argument that the new offence could provide an alternative route to prosecution when a murder cannot be proved. Someone who deliberately conceals information could potentially be held accountable for that concealment, even if investigators cannot establish who committed the killing. But that still requires proving that the person possessed relevant information and knowingly withheld it. An inability to establish who killed a child cannot, by itself, establish those things. 

There is also a practical question: if an adult genuinely responsible for murder faces life imprisonment, would the possibility of a ten-year sentence for silence necessarily persuade them to confess? Or might the pressure fall disproportionately on others whose involvement is less clear? 

Goldsmith has acknowledged that legal experts will need to work through the details of the proposal, and there may be circumstances in which additional disclosure obligations could assist investigations without undermining fundamental protections. However, the difference between compelling someone to reveal information they possess and punishing them because investigators believe they ought to possess it must remain central. 

The death of a child creates an overwhelming desire for answers, and understandably so. But before threatening someone with ten years in prison for failing to provide them, we need to establish that those answers exist. And, more importantly, that the person we're threatening actually has them.