Ewen Macdonald, David Bain, George Gwaze, the Urewera Four and Kim Dotcom are recent high-profile cases the Crown has either lost or been found by a court to have acted outside of the law.
In light of these and other cases, the public may be inclined to ask whether the New Zealand system of prosecution is flawed, or worse, incompetent.
To this question, I answer "no", but add that there are lessons to be learned and dangers to be avoided.
This week has seen the jury acquittal of Ewen Macdonald. The heartache of a destroyed family, the tense relationships, the well-to-do nature of the family and even the attractiveness of the main characters have combined with the "whodunit" nature of the case to enthral our nation.
But can it be said that the acquittal of Macdonald indicates incompetence in our system of prosecution? I am no apologist for the Crown or the "system" but, the reality is, some matters are destined to remain a mystery. Get used to it. Perhaps as a result of the plethora of CSI "add city of choice" television programmes, the public may have come to expect absolute certainty in all cases. But that is not possible.
Our system of justice does not provide jurors with a crystal ball. I do not categorically know, and neither do you, whether David Bain or Scott Watson are killers. We can only derive logical conclusions of probability from the information available to us.
There may, for example, be several probable, or even likely, scenarios available to explain the killing of Scott Guy, the Bain family, Ben Smart and Olivia Hope, but the Crown does not have the luxury of convincing us to the legal standard of "probably" or "likely", and neither should it. The standard applied is beyond reasonable doubt.
This standard is not unobtainable. I believe that, on the whole, juries have shown themselves to take their role seriously and an acquittal will not necessarily imply prosecution incompetence. In the Macdonald case, it seems that both the investigating police and the Crown lawyers did an admirable job. There was, I suggest, adequate evidence to proceed with the prosecution, albeit with lamentable gaps due to no fault of police.
Sex crimes and most murders, for example, are not committed in broad daylight before a note-taking crowd. Piecing together what actually happened is not easy and, despite the efforts of highly trained, well-resourced experts, gaps are often inevitable. So the moral? We as a society must accept that the criminal justice system is not capable of answering all our questions in all cases.
Do not expect too much from it. If we do, we burden it with expectations that it cannot hope to fulfil.
In testing the probability of scenarios, the system goes some way to identify the truth, but the identification of the "truth" cannot always be achieved. Not all cases can or will be proven beyond reasonable doubt; the "truth" will sometimes be unobtainable. Unfortunately for Macdonald, an acquittal is not a positive finding of innocence, and he will undoubtedly live with a cloud of suspicion over him for the rest of his life.
Now for the lessons and dangers. We are reliant on investigators and the judicial system to provide us with as many relevant and reliable facts as possible. But investigators are human. The pressure to "find their man" is immense.
They may on occasion prematurely identify a suspect and construct a case around them. That is the main accusation levelled against police by many who support Scott Watson. They have a strong point and that case is one in which the conviction can only be said to be highly problematic.
At other times the pressure may result in acts of positive deception such as the planting of the .22 shell casing in the Arthur Allan Thomas case. In yet other cases, errors in the investigation may arise as in the case of the Bain prosecutions. These examples have led some to conclude that the adversarial system creates a "game" that encourages such activity.
I reject this. The law of evidence and criminal procedure will forever require adjustment, but do not be deceived into thinking that other systems such as the European inquisitorial model do not suffer from their own problems - they most certainly do. Also, do not be deceived into thinking that investigations are always foolproof in other countries - they most certainly are not.
We are humans and not machines. We must strive for competence, particularly from investigators and prosecutors, but cannot expect absolute perfection.
Wherever there is incompetence, the system must be held to account. Wherever there is active deception, people must be punished.
But acquittals may otherwise be the product of a system that works, even if it may leave us with lingering doubt.
Dr Chris Gallavin is a senior lecturer at the University of Canterbury law school.
- © Fairfax NZ News
Do you think schools should be allowed to seize and search students' smartphones in cases of bullying?Related story: Law will allow seizure of phones