Expert Witness

by Anna Sandiford

  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.

  I spent a very pleasant day at a house in West Auckland once, collecting pollen samples and assisting with the collection of concrete samples and sections of wood from the roof rafters. The owner of the house wanted to stop it being bulldozed during construction of a motorway extension. The only way that could happen was if it could be shown that the house pre-dated the early 1900s — if it did, then it would be protected from demolition by virtue of its age. Both concrete composition and vegetation have changed with time, so by examining samples of both (concrete from the walls, pollen from directly beneath the house) it was possible to provide an indication of when the house was built. Tree ring data also helped determine the ages of the trees that had been felled and used to build the rafters. It was a lovely sunny day when we were out there and the house was in a pleasant little spot. Unfortunately, our combined results indicated that the house was not as old as it needed to be and it disappeared under the bitumen. On this occasion, there may not have been any death and addiction, but there was destruction.

  Having demonstrated, albeit briefly, the usefulness of pollen in a forensic setting, it’s heartening to know that in the world of academic research, pollen analysis of mammoth dung has been able to help in determining the extinction mechanism of mammoths and other large mammals during the last Ice Age, which ended approximately 10,000 years ago, depending on one’s global location. Apparently, a gradual decline in large mammal numbers started around 15,000 years ago and lasted for about 1000 years. This would pretty much rule out a previous suggestion of catastrophic extinction à la the dinosaurs at the Cretaceous-Tertiary boundary of 65 million years ago, as the result of an extraterrestrial object impacting the planet about 13,000 years ago. The study also suggested that mammoths may have had a role to play in the way the vegetation of the time functioned and grew. Scientifically, it’s very interesting but from a general perspective I still find it strange that people are surprised that the large mammals are probably more than just a striking addition to an African landscape, but have actually been significant in its development. I’m pretty sure David Attenborough has known that for years.

  It’s reassuring that analysing excrement can add so much information to our knowledge — an archaeologist I know has spent years analysing coprolites, which are fossilised faecal matter, and preserved (usually desiccated) faeces
. By examining coprolites and preserved faeces for the presence of vegetable fibres, pollen, spores, leaf material structures, bones, undigested food, seeds and such like, we can learn a huge amount about an ancient community’s diet, general health, eating, foraging and hunting habits. Discussion also abounds about what length of time each coprolite represents — did people have more or less regular bowel movements? Coprolites don’t always originate from humans; I know a rock outcrop that contains fish coprolites.

  It’s fascinating what we can learn from poo. The problem is that although preserved faeces are hard when they’re discovered, making them soft enough to study also releases the smell.

  Chapter 12

  Those 1960s, drug-takin’ Fabulous Furry Freak Brothers (and Fat Freddy’s Cat)

  Amsterdam is well known for its cannabis culture and liberal attitude towards this particular drug. While cultivation of cannabis is still illegal in the Netherlands, sale of the end product is not. As soon as someone in the United Kingdom says they’re off for a weekend to Amsterdam, eyebrows go up because everyone knows what they’re up to — not necessarily to see the Ladies of the Night but off to get stoned in a coffee shop. It’s a popular destination for stag weekends and any other poor excuse for visiting Europe and ‘seeing the sights’.

  However, it seems the Dutch authorities have had enough of drug tourists flooding the country and causing untold problems. After originally decriminalising consumption and possession of less than five grams of cannabis in 1976, the Dutch government now plans to limit drug tourism by reserving dozens and dozens of the licensed coffee shops for the use of locals only. Some coffee shops are going to become members only clubs, restricting sales to those with a Dutch debit card, which basically removes foreigners from the purchasing pool.

  To give you an idea of how many people we’re talking about here, two councils in Holland, which between them have eight such coffee shops, announced they will stop the sale of cannabis in an attempt to stem the weekly flow of 25,000 customers. That’s 25,000 drug tourists per week in just two areas. It shows how much of a problem it must be for the Dutch, because that kind of restriction on sale is surely going to have a marked impact on the economy.

  Presumably, the change in the Dutch government’s stance is due in part to the increased strength of cannabis. This has come about as the result of cross-breeding variants of cannabis plants to increase the THC (delta-9-tetrahydrocannabinol) content. Analysis of cannabis samples over time has shown that Dutch cannabis contained an average of 8.6 per cent THC in 2000, compared with 15.2 per cent in 2002. In my experience, this is not dissimilar to the story in England and Wales and, to my knowledge, it’s a similar story here in New Zealand.

  Drugs have been a part of life for Homo sapiens for thousands of years. There is evidence cannabis was being used in 3000 BC and there is suggestion that Stone Age humans had the understanding to develop drug paraphernalia. While a definition of how long ago the Stone Age occurred is variable, let’s say it was tens of thousands of years ago.

  Given the human race’s long affiliation with drugs, and for the purposes of this chapter I’m excluding alcohol, it’s no surprise that drug cases make up a good part of any independent scientist’s casework. Cannabis, which used to occur in New Zealand far more than it does now, has been supplanted by methamphetamine. Rather than needing relatively large areas to cultivate plants plus months to allow for growth, meth can be prepared in a relatively small area in much less time. The profit is greater and, as drugs go, it’s far more addictive, meaning that customers are much more likely to come back for more.

  Still, cannabis remains a popular drug of production but there are differences in the ways different countries use it. Hash oil, which is reasonably common in New Zealand, isn’t some thing I ever saw in casework in England. It’s common enough here that forensic scientists have studied the effect different filtration methods have on the pollen content, bearing in mind that pollen can be used to help determine where the source cannabis plants were grown. Cannabis resin, which is a concentrate of the cannabis plant, is common in the United Kingdom and is mostly imported. It’s sprinkled into tobacco a bit like an OXO cube into a stew and is then made into rollies, joints, spliffs — whatever you want to call them. Adding tobacco to spliffs is a very English thing apparently, whereas Kiwis tend to just smoke cannabis flowers on their own and therein lies another difference: leaves and flowers. Some times the leaf and flowering head material from cannabis exhibits will be weighed together. As any self-respecting cannabis user will tell you, when using cannabis plant material, the flowering head is what gives the best high.

  And as any self-respecting drugs scientist will tell you, that’s because the greatest concentration of the active compound of cannabis, THC, is found in the flowering heads of the female plants. Leaf material is smoked in the United Kingdom far more than it is in New Zealand. Kiwis flog off bags of leaf material (‘cabbage’) to ex-pat Brits who think Christmas has come early because they can score cheap cannabis in New Zealand. They don’t know the Kiwis couldn’t give it away otherwise. International micro-economies at work.

  Although cannabis grows very happily outdoors in New Zealand, there is the problem that someone might accidentally stumble across your plantation or it might be spotted from the air by police reconnaissance missions. An anecdote I heard recently recounts how a woman hanging out her washing on one of the offshore islands glanced up to see what she thought might be the WestPac Rescue Helicopter. Turned out to be a police helicopter from which was dangling a police officer in brightly coloured orange overalls clutching a huge bundle of fully grown cannabis plants to his chest as the wind buffeted him about. More interesting work stories indeed.

  The answer to unplanned removal of cannabis plants is to grow it inside or under cover. Whole houses in the United Kingdom are devoted to growing cannabis plants; the growers pay someone to go in and check on the plants, adjust the growing conditions and generally make sure the junk mail isn’t piling up on the door mat and drawing suspicion. The advantage for the growers of those set-ups is that no one actually lives at the house so if it’s raided by the police only the plants are seized and probably the caretaker; the main players remain one step removed. However, many people just set aside a small area of their premises for smaller scale cultivation.

  One such case was where Mr Jones had grown cannabis plants in a special room in his house. He said the cannabis was for his and his mother’s personal use, because his mother had cancer and it was the only thing that helped her manage her condition. A relevant point here is that there is at least one prescription drug on the market containing the active ingredient of cannabis. However, patients who have been prescribed this drug reported the unwanted side effects that can result from cannabis use — increased anxiety, paranoia or the occurrence of panic attacks, feeling nauseous, dizzy, clammy and the associated draining of colour from the skin resulting in a condition referred to as a ‘whitey’. The patients’ main concern was that the capsule form of the drug didn’t allow them to minimise the dose they received, which is why research has been under way to develop a nasal spray.

  Anyway, Mr Jones’ assertion that the cannabis was for his mother’s benefit, although not legal, might have some sway with the court on compassionate grounds, coupled with the reported benefits. The police took a different view and were of the opinion that Mr Jones had grown this lovely, juicy crop of green, green cannabis to dry and sell to anyone willing to pay.

  Mr Jones said his mother used to smoke cannabis by the traditional cannabis cigarette method. Unfortunately, Mother Jones had to give up smoking so her son started making cups of cannabis tea for her instead.

  Part of my job in the case was to determine how many cups of cannabis tea the seized weight of cannabis could have made and whether that number was feasible or not for personal use. When I asked for the cup he used so that I could make a valid estimation, I duly received the most enormous drinking mug I have ever seen.
I was expecting a coffee cup, perhaps a large tea mug at best, but this thing was huge. It meant that seven cups of tea per day increased the volume of cannabis used per day from a few grams to tens of grams. This meant the total volume of cannabis seized wouldn’t have lasted as long with the bowl-with-handle cup compared with a standard cup; it went to the credibility of the story and whether or not the total mass seized could have reasonably been for personal use, as he was claiming. Small cup meant less likely; large cup meant more likely, assuming the court could be persuaded accordingly.

  All seemed well and good for the defendant — I could almost hear his solicitor thinking he could be in with a fighting chance here. Then I asked about how the cannabis tea was made. The order of ingredients and manner in which the drinks were made was crucial to the credibility of the defendant’s account. I needed the defendant’s description of how he made the tea before I said anything else. As it turned out, the way the defendant says he made the tea wouldn’t have released the active ingredient from the cannabis material — which meant the tea drinker would have had a nice hot cup of wet cannabis flowers but wouldn’t have got stoned.

  On the day of the trial, I met with the prosecution expert, which was good as far as I was concerned, because it just so happened he was an extremely experienced scientist who agreed with what I was saying. He was a nice chap, too. We had to sit in a pokey interview room while the trial was in progress and, unusually, we were allowed to sit together — although we were very tactfully reminded not to discuss the case at hand.