Expert Witness (17 page)

This next story is about drug traces on bank notes and also about court attendance, this time where I was involved as a defence expert for a case in Scotland. I only went because my boss was on holiday somewhere exotic and he couldn't make it, so I had to go. After getting stuck on the M1 on the way to Luton airport (pouring rain, stationary traffic for an hour) I missed my flight to Aberdeen and had to get on the next flight, which was to Edinburgh. Happily, the barrister was in Edinburgh so he picked me up at the airport and we drove to Aberdeen. I have no idea exactly how long it took, except it seemed a very long time in a car with someone I had never met. In fact, I had never even spoken to him before. This is the sort of thing your mother warns you not to do.

I spent four days in Scotland. It snowed and there was no heating in the hotel, even though Rod Stewart was apparently a co-owner. All I can say is that despite being born in England he's truly Scottish with iron for blood and thicker vests than I've ever owned. I had no thermals with me. There was porridge for breakfast, though, which was good, as it meant no other meals were necessary for the rest of the day. It arrived in an enormous bath-sized bowl, three inches deep and accompanied with either salt or nowt. I didn't dare ask for honey in case they muttered about me being a southern Sassenach wuss, and spat in tomorrow's porridge. The Crown's scientists came and went. I stayed, in case I was needed, but I wasn't. The Crown wanted to show the tape of the police interview but no one knew how to work the video player. I
know it makes me sound ancient, but DVD players weren't widely used at that time. Rather than allow us to try to work it out for ourselves (three barristers, a solicitor, a judge, three forensic scientists and an assortment of police officers who must have had to deal with videotapes and players on every shift), court was adjourned for half a day so that a technician could drive from Aberdeen to fix it. Only a certified technician was allowed to touch it. The technician duly arrived, pressed a switch, the VCR started to work and we all got back to the trial wondering how life had become so mad and why the technician couldn't have told us over the phone which button to press.

There were many other things about the case that were bizarre including some of the circumstances (the defendant was found guilty; the defendant went to prison; the case was appealed; the defendant was released). I can't really say much more because I'm not sure if there might be some other ongoing issues with it but another odd incident occurred during the original trial. A mobile phone rang (very quietly, I might add). The judge stopped the proceedings and demanded that the offender place at least a pound, but preferably a bank-note of some denomination, into the charity jar he kept on the bench. I leaned over to the solicitor and commented that this was indeed a strange occurrence. He leaned back and said, ‘It's just as well we're not in the court room next door — the judge in there puts people in the cells for an hour if a phone goes off in his court, even if you're a QC.'

T
oday, I am wondering what happened in my life that meant my working day was reduced to boiling the snot of dead people. Because that is what I am doing. I have eight test tubes, I'm in the laboratory and I'm mentally battling with myself about what the contents of these tubes represent. No matter how I look at it, I can't escape reality: it's snot from dead people. This isn't some kind of punishment inflicted on me because I was naughty or did some thing wrong. This is part of a research project I dreamed up, along with some colleagues from England, while we were having a beer in the bar during their 2009 visit to give evidence in the Bain retrial. The reason we started to discuss dead people's snot is because we wanted to see if we could come up with a method to collect pollen from the nasal passages of the deceased that was less costly, time consuming and invasive than the previous method.

Pollen analysis is an area of forensic science that doesn't really get the coverage it deserves. That's partly because it seems to have been painted as technically difficult. However, pollen analysis (and I use the term ‘pollen' here to include spores as well) is not really any different from other types of trace material. The same factors have to be taken into
account when considering collection, sealing of items and examination/processing at the laboratory. The real skill comes in the interpretation because it requires knowledge of botany, ecology, crime scene examination and the forensic arena, in order to be able to make any sense out of it.

When you look out at a meadow or garden in spring time, the sight that meets the eye is of regeneration — new growth, flowers and pretty colours. Floating in among the beautiful posies, billowing grasses and flowering trees are masses of reproduction bodies — pollen and spores. Because not all of those reproduction bodies go on to make new plants, the ones left over are the trace deposits that can be picked up and used by human beings for forensic purposes or for heating our homes. Pollen, spores and microscopic particles made of a compound called sporopollenin, form a component of the fossil fuels we burn in our fireplaces, or in coal-fired power stations. Pollen and spores are also used in the petroleum and gas industries to help find layers of underground rock that might contain those fuels. Of course, those pollen and spores are essentially fossils but the modern ones floating around in the air and settling on surfaces all over the planet are the ones most likely to be encountered in forensic casework, as well as being the ones that cause hay fever. From my academic research perspective, pollen is most commonly used to reconstruct past vegetation communities, which, in turn, tell us about climate and environmental setting at the time the pollen was deposited. For example, I know all about how Auckland's vegetation changed over the last one million years and how it reacted when tonnes of volcanic ash rained down on it from the Auckland and central North Island volcanoes.
It's interesting, it adds fuel to the climate change debate, but it's not often going to solve any crimes. We have to think differently for crime solution.

From the perspective of people who are murdered, their last breath may well contain pollen from the place where they took that last breath. Knowing what plants that pollen represents can some times help investigators determine what happened to a person before and/or after they died. Those of a delicate disposition may want to skip this next bit but going back to my cunning plan of boiling dead people's snot, the problem with the previous method of collecting samples from nasal passages was that it was very invasive. It involves removing the top of the skull with a saw, removing the brain (this often occurs during post mortems anyway), peeling off the basal lining of the skull, breaking through the bony base of the skull and into the nasal passages. The corpse is then turned on its side, a warm water and shampoo mixture is flushed through the nasal passages and the emergent liquid is caught in a bowl as it exits the nasal passages. This procedure requires at least two people, one of whom is usually a forensic pollen expert. Because forensic pollen experts aren't routinely present at postmortems, arrangements have to be made for the pathologist, pollen expert and often a police officer to be present — this takes time and costs money because the pollen expert might have to travel from a long way away. The pollen expert also has to bring a whole heap of kit with them to get the job done, just in case the mortuary doesn't have that particular equipment.

Delaying post mortems is not desirable, because not only does it delay the investigation, it also delays the time until the body can be released to the family for the funeral. On a
personal note, I would also prefer that if a pollen sample had to be collected from a body that the minimum amount of destruction be done to that body.

Another reason why I thought long and hard about how to collect pollen samples from noses without having to remove brains was purely selfish: I don't want to attend any more post mortems than absolutely essential. A post mortem is a fascinating experience and I've always been totally absorbed with how the body functions. One problem, though, is that I have a very sensitive sense of smell and mortuaries and dead bodies usually have strong smells associated with them. The other thing is that I'm not keen on seeing skin being cut.

I know this because the first post mortem I ever attended resulted in me going very grey as the blood drained from my face, down through my torso and into my legs where it was quite happy to stay. The only thing that had happened at that stage was the pathologist leaning towards the deceased's eyes and pulling them back with tweezers to see if the blood vessels were burst — a classic confirmation that the chap had died as a result of hanging (probably a pretty good clue was the weird angle of his neck). Although my brain really wanted me to look because it was interesting, my basic consciousness decided it was a very bad idea and just shut down, which led to the buckling legs and the smirks from the mortuary assistants who'd been watching me very carefully to see how I'd react. I guess one of them lost the bet about whether or not I'd keel over. After that, the skin was cut and ribs of the deceased were cracked with a special tool. Luckily for me, I was being assisted to a stool while that bit happened.

After I'd recovered, though, the rest of the post mortem was
just amazing. The brain really looked like brains do in books, which might sound silly but it's the same as seeing Big Ben or a real kiwi for the first time — they really do look like they look in the pictures. The kidney cross-section was intricate; the intestines were just all over the place like unstrung sausages. I came away from that post mortem fascinated, educated and horrified in equal measure. And embarrassed, because the pathologist was the same one who did the post mortems on Princess Diana and Dodi Al Fayed. He was very gracious about my temporary staggering and never mentioned it again. He must see that sort of reaction all the time.

So here I am today, boiling snot from dead people to see whether our new, non-invasive technique recovers as much pollen as the old brain-removing approach. I'm happy to say that it does, which, if people use it, means less time wasted at post mortems, less cost and, for me, less chance of having to go to post mortems at three in the morning.

As far as casework goes, those involving pollen don't fall in to any dominant case category, mostly because pollen is such a versatile trace material and because it's present everywhere including, as we have seen, up people's noses. It's not like cases involving glass fragments that, in my casework experience, most often relate to burglaries, break-ins or car theft. Cases involving drug traces usually relate to drugs. Cases involving blood spatter relate to some sort of crime against the person (or, occasionally, against an animal). Pollen as an evidence type occurs across a wide range of cases.

One of the interesting applications of pollen is determining
the geographical location in which drug plants were growing when they were harvested, such as
Cannabis sativa
(cannabis plant),
Papaver somniferum
(opium poppy used for making heroin) and
Erythroxylum coca
and other species of
Erythroxylum
(used for preparing cocaine). I also assume this could apply to
Ephedra
, which can be one of the source materials used in the manufacture of methamphetamine, or as it's more commonly called in New Zealand, Pure or P. This would be a good research topic if anyone feels like giving us some funding for it. We've undertaken pollen analysis of drugs for intelligence purposes and had good results but I can't tell you any more about it because it's probably classified information.

A similar use of pollen analysis is to determine whether different batches of cannabis flowering head material grew in separate growing seasons or just one growing season. Both of these types of cases involve washing the pollen grains out of or off the main drug material and examining what other pollen grains are present. Because plants have ecological niches, we use the pollen to paint a virtual picture of the environment in which the plants grew. In the case of cocaine and heroin, it can also be possible to use the pollen content to identify not only where the original plants were grown but also where in the world the pure form of the drug was diluted, or ‘cut'.

Other examples of pollen casework are for confirming or refuting alibis. One case involved a defendant who said he had not assaulted a woman in a specific location in a park, although he accepted he had walked through another part of the park. Pollen recovered from her clothing and his shoes showed they had been in the same area of the park as the complainant had indicated; the pollen therefore was not consistent with
the defendant's account of events. The reason pollen works in those kinds of cases is because the proportions of different pollen types vary rapidly over relatively short distances, in the order of metres. It means that a ‘pollen signature' in the middle of a park will be different from the pollen signature around the edges, or the pollen signature in the middle of your garden will be different from that at the edge of the garden. It therefore stands to reason that the pollen signature at a murder scene in an urban street will be wildly different from the pollen signature in Auckland's Waitakere Ranges, where the body may be dumped.

Other uses of pollen might be to help determine where a person died or what happened to them after they died. I had a case once where a woman's body was found, intact, in a suitcase by the edge of a tidal river. The puzzling thing was that her clothing and, in particular, her hair, had pollen on them that didn't match any of the locations of interest in the case. It was a while before I realised that no one had taken a sample of the river water to see what had been in it; it was perfectly possible that the unexplained pollen had been carried in the river water and deposited on her as the tide washed over the suitcase and soaked into the contents.

In war crimes investigations, pollen has been used to determine whether or not bodies in mass graves were killed elsewhere and transported to the grave. This had serious implications in the late 1990s, during the extended periods of unrest in Central Europe. Mass graves used to bury victims of genocide were dug up again by the perpetrators. The bodies were removed and reburied in other locations, with fewer bodies in each grave. By doing this, the perpetrators said those
people had not been the victims of genocide, but had been killed in much smaller confrontations — it's more plausible to explain four people being ‘accidentally' shot in crossfire than 50. War crimes investigators then exhumed the smaller graves and took soil samples from the clothes of the victims. In one case, the soil and pollen tied the exhumed bodies with a mass grave in a different location, which, in turn, provided support for claims of genocide.

The solution of a very high profile double murder case in the United Kingdom in 2002, that of Holly Wells and Jessica Chapman, was assisted by pollen analysis. The two 10-year-old schoolgirls went missing in August, during the English summer. After a highly publicised missing person's search, their bodies were eventually discovered near the edge of a Royal Air Force base in the county of Suffolk, eastern England. Pollen analysis of debris from the perpetrator's car helped link him with the site where the girls' bodies were found. The girls had been killed by their school caretaker and his girl friend helped by providing him with a false alibi, although she was not found to have had any contemporaneous knowledge of him committing the crimes. He received life imprisonment with a minimum of 40 years to be served. She was sentenced to three and a half years for perverting the course of justice, served a total of 21 months and in 2004 was released on probation.

For forensic pollen work, pollen experts might be limited to sediment scraped from the knee of a pair of trousers or perhaps pollen collected from the heads of cannabis plants, but any sort of sediment can be examined for pollen. The thing with pollen cases (with the exception of drugs) is that the casework can involve crimes against the person, which are some times the
most difficult to work just because of the distress element. However, it's not all about death and addiction.