Expert Witness (6 page)

Many top-level scientists agree that the
CSI
effect exists and it affects how people view them. Bob Shaler was the man charged with handling DNA identification after the World Trade Centre bombings, so he knows his stuff. It's disappointing for many when he says, ‘I was a crime lab guy, but I was never the person portrayed on TV. That person doesn't really exist.'

The
CSI
effect has also been felt as far as organisations like the United Nations, which is involved with what is referred to as ‘wildlife forensics'. This is the branch of forensic science applied to issues around poaching, import/export of rare, exotic and controlled species. It's a fascinating area of science. The UN is looking to adopt a forensic science approach to assist in managing the problems of illegal fishing. At a UN Food and Agriculture Organization workshop in Rome in 2010 they discussed what techniques could assist and how. As usual, DNA analysis was at the fore, probably for a combination of reasons: it's very well known and it has huge application. DNA analysis can be used to identify fish species, which in turn can answer the question of whether it's a species that shouldn't
be fished. Chemical analyses are also applicable in wildlife forensics for testing bones and other items to identify what nutrients were absorbed by the creature when it was alive and therefore from where they were caught, which can determine if the catch came from a restricted area. I always say that there is no end to the types of casework to which a forensic science approach can be applied and this is a perfect example. Particularly given that one participant at the UN meeting described how a group convicted of illegally trading abalone confessed to learning how to destroy evidence by watching
CSI: Miami
.

Just as an aside, and following on with the wildlife DNA theme, a sign that this is an expanding area of forensic science is when sessions specialising in wildlife forensics are included in conferences such as the 2010 Australia and New Zealand Forensic Science Society 20th International Symposium in Sydney.

Wolves have been a protected species in Europe for some time, and since the 1970s, have been protected in Italy. A number of wolves were found killed and some times mutilated (the muzzle missing from at least one) in the Genoa region. A man was eventually arrested and a necklace of teeth in his possession was seized. The teeth were sent to the Italian Institute for Environmental Protection and Research (ISPRA) where wildlife specialists extracted DNA. As with any case like this, unless there is a database against which to compare results, the results themselves are more or less meaningless. However, there is in fact a DNA database for wolves and other large predators, used to assist with population monitoring. The DNA is gathered from many sources including cadavers
and faecal matter (not forgetting other possible sources such as fur, skin, bones). Six separate wolves were identified from the necklace using the DNA database. Obviously, not all killers wear their victims' teeth, but keeping mementos of hunting is not at all unusual and it makes perfect sense to use trophy items to attempt to link a possible offender with an offence.

Just to finish my ranting about the
CSI
effect, it was very gratifying to hear one of the world's foremost DNA scientists and pioneers of DNA in forensics, Dr Peter Gill, say exactly the same thing, specifically about DNA. Dr Gill's general sentiment was that
CSI
and similar programmes don't really represent the way in which forensic science works in the real world. Programmes like those give the impression that if a DNA profile is recovered from a crime scene and you have a suspect then it must be the suspect who committed the crime. It doesn't necessarily follow that a suspect is guilty of that crime because there are so many other things which have to be considered. Forensic scientists shouldn't necessarily just report (or review) the science in isolation
—
the framework into which that science fits is crucial for the proper understanding of what the science is telling the trier of fact (usually a jury and/or a judge). It is then for the trier of fact to decide what weight to apply to that evidence when deciding on the ultimate issue, which is usually down to two choices: guilty or not guilty.

Forensic science can, of course, also be used for investigative purposes
—
and it may take an investigation down a different track from the one the investigators were expecting. The important thing is that the investigators should take that
scientific information into account when deciding what to do next
—
just sticking with their previous track of thought may be neither appropriate nor correct.

My favourite quote from Dr Gill is: ‘The scientist is not there to prosecute anyone. Whether the individual is found guilty or innocent has no bearing on the science.' Dr Gill makes an extremely valid point. All forensic scientists should be impartial and unbiased in their reporting
—
with no exceptions.

D
iscussing forensic science in theory is one thing, knowing how that applies in the real world is entirely different and not at all like
CSI
. It's the same with any subject: you can read as much as you like in books and scientific journals but the time you
really
under stand it is when you actually do it for the first time, hands on. The next best thing is to learn from case studies, particularly for people who are interested in forensic science but not necessarily wanting to do it for a living, such as the sorts of people whom I assume will be reading this book.

Scientific theory and research do, of course, have their places in forensic science. Ongoing research is the stuff that moves the science forwards which, in turn, allows more and more areas of science to be presented as evidence in court. Without research, forensic science would become stuck in the proverbial rut. It's also important to refine techniques that have already been developed just so that we can ensure the methods being used are up to the job or are replaced with some thing quicker, more reliable and cheaper, much to the bean-counters' delight. All forensic laboratories run on tight budgets so the cheaper a technique becomes, the more samples can be tested or the more testing that can be applied in any
given case, which generally leads to more questions being answered and a greater chance of arrest, charge and successful prosecution of the correct people.

An example would be development of a new technique to collect pollen from the nasal passages of deceased people. The old method involved several people for several hours in a mortuary waiting for the opportune moment to roll a body and wash out the nasal passages; the new technique involves a few minutes, a lidded test tube and a brush. Much cheaper, quicker and therefore much more likely to be used. Another example is recently completed research that looked at how knives cut through clothing that is well worn (as opposed to new fabric). A simple bit of work but it will help deal with those difficult questions a sharp barrister might ask about the differences between stab tests being undertaken on a new pair of jeans instead of jeans that had been worn for months, like the ones forming the exhibit in a case.

The successful conclusion of a case often lies in how much money can be spent on it, not on the limitations of science or police ability — an uncomfortable truth but that's the reality of modern day police work and forensic science. Many people will consider that it isn't ethical or right for modern society to place a monetary value on crime investigation, but like it or not, that's just how it is; same as it is in the health services, hospitals, child protection services, fire services, refuse collection, in fact all publicly funded organisations. When I worked in England, there was a seasonal lag in drug trace cases in the second quarter of the year because the police budget had run out and the new one didn't kick in until April.

If we take a crime such as murder by gunshot, the number
of personnel involved is enormous — and all of them have to be paid: initial police attending the scene, ambulance crew, pathologist plus mortuary assistant(s) to conduct the postmortem, police officers involved with the case with sometimes several officers in charge of the crime scene if it's a large one, with one officer per body and an exhibits officer to coordinate item collection, logging, tracking, several crime scene examiners, finger print examiner(s), ballistics expert(s) and toxicologists to analyse and interpret results from blood and other body samples.

Then there's the cost of scene equipment, with disposable items such as scene suits, bootees, gloves, face masks, chemicals, evidence bags, transfer of the body to mortuary, hospital costs, sample analysis costs, courier or transfer costs (exhibits and items from scenes have to be transported by secure means in order to ensure continuity of the item and continuous chain of custody) — the list rolls on, even before we get to the cost of legal services, the courts, judges, etc. It's all a hugely complicated, money-spending machine that is vital in order for you and me to sit at home and feel a modicum of safety.

What I plan to do in this chapter is briefly discuss why we bother to examine the science at all, what makes an expert an expert in what they do and why it's important that an appropriate expert is instructed.

Purely for argument's sake, let's say there's such a thing as a straight forward murder case. While I've never had the experience of working with such a case, it should be pretty obvious that shooting another person in the heart is generally
going to result in the heart owner's death — we can all understand that. Why then would we bother to examine the science?

Well, some times questions arise from this sort of death such as how far away would the shooter have been to cause that injury; could Weapon A have caused that injury; how quickly would the deceased have died? All these questions have an impact on determining the circumstances of the death, which is crucial to under standing what happened and who, if anyone, was to blame or was at fault. So back to the original observation that everyone knows shooting another person in the heart usually results in death
—
while we know what happened on a superficial level, it requires an expert to talk about the detailed mechanics of what
exactly
happened, which often tellingly includes
how
and
when
it happened.

In the circumstances of our straight forward murder we'd need a ballistics expert to talk about the firearm, firearms discharge residue and projectile trajectory, a pathologist and/or medic to talk about wound geometry and speed of death, and maybe a blood pattern analyst to talk about relative locations of people and items at the time of the events. That's on top of the usual analyses such as DNA of any blood spatter recovered from moving items (such as a person who ran away after firing the fatal shot) or toxicology to determine whether the deceased was drunk, affected by drugs or toxins, or was taking medication at the time of their death.

If we don't examine these issues then we can't be sure of what happened, particularly if there's no one left alive to tell us. Even if anyone is still alive, there's no guarantee that they'd want to tell the police the truth about what happened. What we're left with is what we can see, measure and collect and
some times, even more importantly, what we can't see but can still collect, measure, investigate and magnify. To borrow from
CSI
and Grissom for a change, these are the silent witnesses that were present and can tell us about what happened without uttering a word.

After the David Bain retrial had finished on 5 June 2009, there was a line in the Christchurch
Press
newspaper that really perplexed me. It read,
Every piece of Crown evidence was put under the microscope [by the defence] in a way possibly never seen before in New Zealand
. My first reaction to this was
what?
How can it possibly be that in a country like New Zealand, which has its judicial roots in the same system I grew up in, the media thinks examination by the defence of the evidence being put forward by the Crown is in some way an exceptional situation?

Either the media has no idea what happens in court rooms, which cannot be the case because some of these reporters are
court
reporters, or the media genuinely had never before seen anything like the investigation undertaken by Bain's defence team. Well, I for one don't want to believe that and I'm sure no one else wants to believe it either — how can there be any trust in a justice system that doesn't robustly challenge what is being presented?

Best case scenario is that the media was sensationalising what it had observed. Worst case scenario is that the statement is true. If it's the latter then there is clearly a whole lot of work that should be done in casework that currently isn't being done.

 

Having established that even simple circumstances can be assisted by science, the question then asked is why instruct
an expert? Why can't information just be put before the court for the court to decide what it means?

Although the trier of fact knows that to shoot someone in the heart is probably fatal, they often require assistance with information that falls outside what could be called ‘common knowledge'. Experts give the court advice, in the form of evidence, on issues that don't fall within the court's ordinary knowledge or experience. That usually means an expert has had some form of special training or study.

For the areas of information that require specialist knowledge, the police have an on-tap pool of expertise into which to dip its toes, or jump in wholeheartedly. In New Zealand, it has ESR Forensic. In England and Wales there is a bit more of a choice because of the larger population size. There police forensic work is put up for tender and there's a big scrap over which organisation gets what. There are 43 regional police forces plus the British Transport police, each requiring forensic science services. Some forces choose to do the work in-house, some farm all of it out, some do a combination. Finger print work, for example, has traditionally always been done in-house as has road traffic incident investigations (crashes to you and me). The Forensic Science Service is the equivalent of ESR Forensic, in that it used to be run directly by the government but is now run as a separate business unit. There are other organisations such as LGC (Laboratory of the Government Chemist) that was privatised and became such a significant player that it was able to take over another independent laboratory, Forensic Alliance. Between them, the FSS and LGC hold the majority of the police contracts but things have changed recently, with more and more tender work being won by smaller service providers.

But what about the independent sector? People need independent sample analysis — blood alcohol samples, DNA samples, glass analyses, drug sample analysis, urine samples from prisoners (because they're not supposed to be taking drugs in prison, you know). England and Wales have several smaller independent laboratories undertaking this kind of work but New Zealand struggles somewhat in this department because of its population size. This means that people like me spend time arranging for samples to be sent overseas to be analysed.

Back to the original question now: why is there any need to employ an independent expert? It comes down to basics: an independent quality control check. When I present lectures on this topic, there are six cases to which I refer. As with New Zealand, England and Wales has its fair share of problems when it comes to forensic science and there are unfortunately several other cases to which I could refer, but those below are the least technical and the most demonstrative. There are of course several high-profile New Zealand cases that could be used as examples but I intend sticking to English cases because people get tied up with the emotional aspects, which cloud the importance of the science. Emotions and science don't mix so in New Zealand I talk about English cases and, in England, I talk about New Zealand cases.

Angela Cannings and Sally Clark

In 1989, Angela Cannings' baby died at the age of 13 weeks. Another seven-week-old son died in 1991 and in 1999 her 18-week-old son died. After the first death, the view seemed to be that this was unfortunate — poor lady. The subsequent
deaths were viewed as some thing else and more than just coincidence — how could a woman have more than one baby die as the result of natural causes? She was charged with murder, tried and convicted.

Sally Clark gave birth to a boy in 1996 but he was found dead in his Moses basket at 11 weeks of age. Death was certified as ‘natural causes'. She later had another boy in 1997 who, eight weeks later, suddenly collapsed. The parents requested a specialist pathological examination, as did the hospital paediatrician. Unfortunately, this did not occur and the postmortem was performed by the local Home Office pathologist. After four weeks' delay, the parents were arrested. The pathologist had reported retina and brain damage attributed to ‘baby shaking'. Review of the first child's death resulted in the original certification of natural causes being replaced with smothering. In July 1998 Sally Clark was charged with the murder of both babies. An expert paediatrician for the prosecution said during the trial that the chance of a double cot death in the Clark family, at one in 73 million, was ‘vanishingly small'. However, it was accepted by both the Crown and the defence that there was no evidence both babies died of cot death. The same expert witness gave evidence in the trial of Angela Cannings. Crown evidence was that Mrs Cannings had smothered her children.

Figures from the Care of Next Infant (CONI) charity are that one cot death occurs in every 8500 babies, but after one cot death the risk of a second actually increases to one in 200. The statistic of 1:73 million quoted by the expert in the Sally Clark case is five times smaller than the chance of winning the English lottery.