ESR Forensics boss Dr Keith Bedford has had oversight of the forensic evidence in virtually every high-profile court case in New Zealand in recent decades, some of which are illuminated in Prime TV's new show Forensics.

1 In Forensics' first episode, ESR scientists use 3D laser scanning to recreate the crime scene of murdered taxi driver Hiren Mohini. How much of that technology was developed by ESR?

Forensic science is often called "magpie science" because we pinch developments from all branches. 3D laser capture has been around for a while but we've done significant work at ESR to develop its forensic use. The best thing about it is it's a dimensionally accurate way of capturing a crime scene so we can take measurements within it for things like blood pattern analysis and bullet trajectories. If a new scenario develops, we can go back and do calculations in a way that's easy to make clear in court using features like fly-throughs and helicopter views. In the Bain case, for instance, going back to consider scenarios would have been so much easier if the crime scene had been captured by 3D laser before the house was destroyed.

2 What are the most common misconceptions about forensic work caused by TV shows like CSI?

Some of my staff refer to CSI as "Crime Scene Inaccuracy". We do have staff that attend crime scenes but they're civilians who don't have authority to question. We laugh about the actors' designer clothes. One of my staff said it's more like being a teletubby with all the protective gear they have to wear. Another misconception is that you can resolve a crime in an hour of commercial programming, whereas for us it can take days or weeks of laborious, intensive work.


3 What kind of person makes a good forensic scientist?

We need people who have got good attention to detail. Forensic scientists who attend crime scenes work long, anti-social hours and crime scenes can be pretty grotty. You have to be able to explain clearly in court, under pressure, the significance of what you're saying - not just the data but what it means and the appropriate weight that should be placed on it. For example, it's come to light that miscarriages of justice may have occurred in the US for decades because some hair examiners placed far too much weight on hair comparisons which the FBI now acknowledges were overstated. In New Zealand we've worked very hard at fairly representing the weight of that kind of evidence.

4 Some high-profile miscarriages of justice were exposed in the mid-1990s such as David Bain, Arthur Allan Thomas, David Doherty, Mark Lundy and Teina Pora. Do you think there are others?

I think New Zealand's had a very, very small number of miscarriages of justice. It's interesting reflecting on how our legal system deals with these claims. No human has omniscient power to determine if justice was truly done so the appeals process basically retreats into questions about the rules and whether they were followed correctly.

5 Do you think we rely on DNA evidence too much?

A good third of ESR's activities would be DNA-related. There's a danger we could lose expertise in other areas like physical evidence. DNA's brilliant at determining if a person was present at a crime scene but blood pattern analysis can give other useful information about the person's movements. We're one of the few labs in the world researching RNA, which enables us to detect the origin of DNA. For example, if a woman alleges she's been drinking with someone and has then been violated with the bottle, DNA testing can only say her DNA is on the bottle neck but RNA analysis may indicate the cells are vaginal in origin.

6 How cutting edge is ESR internationally?

We punch well above our weight. New Zealand was the second country in the world to start a DNA databank. ESR has spent 10 years developing a new computer-based DNA tool that we've sold worldwide. It's used to separate out individual DNA profiles from mixed samples. One reason for the high standard of our forensic science is that, unlike the US, we have a single police force and forensics provider so we can ensure standard police procedures reflect best practice.

7 ESR is paid by police to provide forensic evidence, so how can you claim your findings are independent?

Through the professionalism of our staff. We do work very closely with police to obtain the best evidence but we're not an arm of the prosecution. When a case gets to court we have to deliver the evidence as objectively as we can. There's always a risk that if you get provided with a certain set of information you might pre-judge it. It's called contextual bias and it's one of the challenges being debated internationally. We take a lot of trouble to ensure the integrity of the process, for instance, physical evidence such as bullet mark comparisons are always cross-checked.

8 Is the cross-checking done "blind"?

We always cross-check when the first scientist thinks there's either a class match (e.g. a brand of shoe) or a match (e.g. a particular shoe.) But the second scientist knows that a match must have been found, so that's one of the things we have to grapple with. Ultimately we strive for perfection but it might be that things are not 100 per cent perfect all the time. Humans are fallible.

9 Does ESR ever work for defence lawyers?

It would be impossible for us to work for both sides and not tell the police if we found something. Occasionally, by agreement, we've done further analysis and made results available to all parties.

10 How has your job affected your family life?

My wife and I were foster parents for the Department of Social Welfare. As committed Christians we saw it as something we were meant to do. Our children were young at a time when my work wasn't such a pressure on home life. We ended up adopting two Maori children who came to us at ages 3 and 18 months. You'd think at that stage there was time to try and put some things right. It was challenging but I don't regret it. Seeing them come out the other end of some difficult circumstances is wonderful. They're adults now and have all married. We're very proud grandparents of nine mokopuna. We adopted our third child when we discovered we couldn't have children of our own.

11 You have significant vision impairment. How does this affect your ability to do your job?

It's been a bit of a roller coaster for 20 years. My level of sight has varied along the way. But I've been able to achieve all I've needed to.

12 You're 65. Do you have plans to retire and do you have a succession plan?

I haven't set a date to retire but I do have a succession plan. It may be not far off the time when a transition period would be appropriate. It's my responsibility to ensure others are being prepared to step up.