Tuatara: Volume 30, Issue 1, December 1988
Deer Velvet And Palynology: An Example Of The Use of Forensic Palynology In New Zealand
Deer Velvet And Palynology: An Example Of The Use of Forensic Palynology In New Zealand
Forensic palynology has the capability of proving or disproving alibis; connecting suspects to the scenes of their crimes; connecting an item or items to either the scene of the crime or to suspects; and sourcing items, including drugs, to their point of origin. A brief history of one of the earliest New Zealand cases, involving the theft of deer velvet, is presented as an illustration. Palynological evidence given in this case is summarised and placed in context with other evidence.
Key words: Forensic palynology, palynology, criminology, pollen assemblages, case history, deer velvet, New Zealand.
The objective of this paper is to present evidence of the usefulness of palynology in forensic science (Mildenhall, in press), with particular reference to New Zealand. page 2 It is written primarily with the lay person in mind and will be devoid of undefined scientific terms. The paper takes the form of a summary of the evidence presented at a trial that generated much publicity. Although all the information about this trial can be gleaned from the newspapers of the time, the names of the people involved will not be mentioned in this paper.
One scientific term that is unavoidable is “palynology”. Palynology is the study of spores and pollen, the very small fertile bodies of all plants, usually disseminated by air. The term pollen assemblage refers to the total range and relative numbers of different types of spores and identified plants to avoid confusion over the use of common names, which often apply to different types of plants in different countries.
A pollen sample is obtained by acetolysis, which entails heating the rock or soil sample with a mixture of one part concentrated sulphuric acid and nine parts acetic anhydride. The organic material is then separated by centrifuging, floated off and mounted on glass slides ready for examination under a high-powered microscope. The exact technique varies with the material to be analysed; acetolysis is not used if viable pollen is to be studied.
Palynology has proved useful in a number of forensic cases over the past ten years, although not all cases have come to court. Both New Zealand Geological Survey and Botany Division (Department of Scientific and Industrial Research or (Dsir) have been active in this field. New Zealand Geological Survey's involvement in forensic palynological work has been the result of a number of factors. Firstly we are close to Chemistry Division (Dsir) in Lower Hutt, where the bulk of New Zealand's forensic science is carried out and it is but a simple matter, and easily demonstrated in court, to pass samples from hand to hand without recourse to couriers. We are therefore able to work closely with the other forensic scientists involved in each case. Secondly, New Zealand Geological Survey provides a forensic petrological service and in many cases it is logical to provide a palynological service in the same laboratory at the same time. This avoids problems of explaining continuity of sample handling, a bugbear of many court cases, since it must be always quite clear where individual samples were at any instant during an investigation. Thirdly, our staff of four palynologists have expertise in a variety of palynological fields which are of potential use to the Police. Finally, we have been able to build up a case file from experience gained in the field over the last ten years.
The purpose of palynological evidence is to attempt to identify and then correlate spores, pollen and other acid resistant organic materials at the scene of a crime, or on a suspect, with each other. In essence we try and determine the relationship between a suspect and the scene of a crime, by linking an item left at the scene and a suspect, or an item at the discovery scene with the scene of the actual crime. We also attempt to disprove or prove alibis, and source items to their point of origin. Palynology can also be useful in cases of suspicious death where poisoning is thought to be involved, particularly with botulism and honey poisoning, although this is more the role of the medical profession. There are many problems with forensic palynology and some of these are briefly mentioned in Mildenhall (in press).
Forensic palynology is a relatively new science. Erdtman (1969) in a chapter headed “pollen analysis and criminology” described several ways in which palynology has solved crime, including a murder investigation in Vienna, Austria, in which a unique combination of spore and pollen types on a suspect's shoes pointed to the scene of a murder, even though at the time the body of the murdered person had not been discovered. The diet of a murdered person can sometimes page 3 be determined by pollen analysis of stomach and gut contents and by analysis of faeces (copropalynology). Archeologists use these methods in determining the environmental, social and cultural conditions of primitive peoples by study of the plant remains associated with buried bodies (Leroi-Gourhan, 1975; Stead et al. 1986).
Case History: The Case Of The Stolen Deer Velvet
This case history involves the theft of deer velvet (antlers in a soft state). Some mention of the case has already been made in the literature by Mildenhall (1982), Skinner et al. (1988), and Mildenhall (in press). This description of the case in greater detail permits the role of forensic palynology to be placed in context, as well as confirming that it is only one of a series of techniques that are available to the courts in seeking out the truth.
On 27 February 1980 the Police executed a search warrant and seized a large quantity of deer velvet from a suspect's house. The deer velvet was later identified as having been stolen three months previously from Ohinepaka Station, Wairoa. The velvet was found in a freezer in a garage at the suspect's home and weighed 37.5 kg; the original amount stolen was estimated to be over 100 kg and worth about $16,300. The suspect was charged with stealing the velvet on 23 November 1979 and an alternative charge of receiving 66 pieces of deer velvet between 23 November 1979 and 26 February 1980 was also laid. The suspect denied the charges and maintained that the velvet had been colleccted by him over two seasons and was being stored until the price of velvet, which was low at the time, rose. The suspect elected trial by jury.
The non-palynological physical evidence
The theft was first noticed by the manager of the deer farm on the 23 November 1979, when a large amount of velvet was found to be missing from a padlocked freezer on Ohinepaka Station. Also missing was a wool bale sack, which had been covering the floor of the freezer, and a quantity of sausages. The stolen material consisted of 97 kg of A (= first) grade and 20 kg of fourth grade velvet, some of which had distinguishing marks caused by the cutting equipment used at the time to cut the antlers off the farmed deer. These distinguishing marks were found on some of the velvet located in the suspect's freezer. Moreover, string marks on the antlers were consistent with those left by the manager's method of hanging the antlers in the freezer at Ohinepaka Station.
One of the stolen antlers had come from an animal that the manager had been keeping a close eye on because it had an unusually shaped antler with a break at the base. Furthermore, some of the antlers still had string attached, consistent with string used at Ohinepaka Station. A wool bale sack, similar to the one stolen from the station, was found in the corner of the suspect's garage.
The high quality of the velvet recovered was regarded, in part, as being due to the method of storage. The velvet recovered was found stacked in a small freezer, but if the antlers had been frozen in that position from a soft state then identations would appear on the velvet. These indentations were not apparent on the recovered velvet. It was quite clear that this velvet had been frozen individually by hanging in a large freezer, attached by string. In the event of thawing and being refrozen some marks would be apparent on the antlers. Stags grow antlers annually, and being at their most valuable state when soft, the antlers are usually harvested about sixty days after the commencement of growth, in November through to page 4 January, depending on the area. After harvesting they are hung up to cool in such a way as to prevent blood loss, then hung in a freezer until frozen, and finally stacked. The retention of blood adds to the weight, and the subsequent possible value of the antlers, which, if not frozen, would be unsaleable within 48 hours.
Since the suspect maintained that he had obtained the antlers over a period of two years hunting in native bush, and that he had carried the velvet out attached to his belt, it was difficult to see how the velvet could have been of such high quality, since some damage would be unavoidable considering the stated method of transport. Experienced hunters giving evidence at the trial confirmed that the method of carrying velvet, as stated by the accused, would cause much damage and that hunters would normally carry velvet tucked down the front of their jerseys or well wrapped up, because “it was like gold and has to be well protected”. Considering the suspect's statement that he had collected the velvet over the previous two seasons, further evidence from experienced hunters indicated that, because the harvesting period for velvet was so short, the amount of velvet seized by the Police was too great to have been collected in a two year period of time from free ranging deer. The hunters also maintained that it would be impossible for one man hunting alone to get 18 kg per month and that most of what was obtained would be well below A grade quality. It was estimated that a total of only about 20 velvet carrying stags would be shot in the area per year, averaging three animals per week for a full time hunter, at an average weight of about 1 kg of velvet per stag.
Evidence also presented suggested that velvet was usually cut off free ranging deer by sawing, not cutting and that tourniquets were not normally used when collecting velvet from free ranging deer killed in the wild. The suspect explained the existence of the string and string marks on the velvet by stating that he had applied a tourniquet to the antlers immediately after cutting them off with bolt cutters or a saw (which he could not produce in evidence) in order to stop blood loss. He also maintained that the string had been given to him, along with the wool bale sack, by an employee from a local Lands and Survey farm.
The police recovered 66 pieces of velvet in total, but of these only 10 matched in colour and development, indicating that they had came from the same five deer. If the suspect had done his own harvesting then a higher degree of pairing would have been expected. This was explained by the suspect as resulting from damage to some antlers when the animal fell to the ground after being shot, and the damaged antlers being left in the bush. However, experienced hunters stated that all velvet was of some value and that it was most unusual to leave damaged antlers after the effort of shooting the deer.
Evidence was also presented from an agent for a velvet-buying company, who examined the recovered velvet and maintained that it could only have come from animals growing in a very good environment, possibly pasture. This was on the grounds that animals from the wild always have a percentage of malformed or damaged velvet, and that only about 25% of deer velvet collected in the wild would be of A grade quality. This witness estimated that the antlers examined contained well over 60% A grade velvet, while another witness put this figure at 90% A grade velvet.
The non-palynological forensic evidence
Forensic scientists from the DSIR were called on to examine the velvet, wool bale sacks, twine, wool bale string, and the cutters used at Ohinepaka Station to remove the velvet from the deer. The scientists were unable to confirm that the page 5 cutters were used to cut the antlers, although it appeared that a similar two-bladed instrument was used, which cut into the antlers a small distance and then snapped them. Hence there was no evidence to prove or disprove that the cutters from Ohinepaka Station, which were presented in court, were the ones used. The string at Ohinepaka Station was the same as that attached to the stolen deer antlers, but it was of a fairly common type in wide use. The stolen wool bale sack was similar to those still in use at Ohinepaka Station, but again they were of a fairly common type and in wide use.
A quantity of dung was found on one of the stolen antlers. Examination of the material indicated that it came from an animal that fed off pasture grass and not on bush vegetation.
Six soil samples were collected from the deer pens, two samples from inside and outside the stolen wool bale sack, one sample from a wool bale sack at Ohinepaka Station and three samples from three separate antlers found in the suspect's freezer, one of the samples coming from the base of one of the deer antlers. Petrological examination of all 12 samples showed that they contained minerals and rock fragments consistent with coming from a similar source, and that they all contained a large amount of organic matter that appeared suitable for pollen analysis.
The palynological forensic evidence
The twelve petrological samples were also examined palynologically, and the plants from which the spores and pollen came from were identified in ten cases. However, two of the samples, from material adhering to the stolen antlers, did not contain any spores or pollen. All ten samples were consistent with derivation from a cultivated grassland source and no sample contained evidence of having been derived from a forest or bushland environment. The similarity of the pollen assemblages from the stock pens and the wool bale sack at Ohinepaka Station with those on the stolen wool bale sack and on the base of one of the stolen antlers suggested that they were derived from a very similar source. The combination of spore and pollen types suggested that the farm on which the stock pens occurred was the original source of all samples. It was impossible for the samples to have come from a grassy clearing in bush or forest as the pollen assemblage from the clearing would have been dominated by pollen from the surrounding trees. The percentages of spores and pollen, given below, could not be derived from soil samples cultivated plants suggested derivation from a cultivated area in which both exotic and native plants occurred together (Table 1).
|List of plants identified|
|pen||pens||bale||wool bale||wool bale||antler|
|Liverworts; mosses; etc.|
|Pteris cf P.|
|Total spores counted||65||-||13||4||12||10|
|Conifers: Agathis australis|
|Pinus cf. P. radiata||1%||4%||X||2%||X|
|Knightia excelsa||X||X||X||Xpage 7|
|Nothofagus brassi group||2%|
|N. fusca group||X||1%||2%||3%||X|
|Salix cf. S. nigra||2%||X||2%||X||9%|
|Total pollen counted||145||-||161||137||125||158|
|Total spores and pollen||210||-||174||141||137||168|
|Notes:||1.||Column one is a selected sample from the stock pens; column two consists of a composite of the other 5 samples from the stock pens, with only those taxa not found in the first sample being indicated.|
|2.||The percentages are based on counts of pollen only (spores are not included). Only those plants forming 1% or more of the total pollen count are included in the above percentages.|
|3.||X = present in the sample;|
|? = uncertain identification.|
|4.||The sample from the outside of the wool bale sack collected from the suspect's garage had a sparse assemblage in which grasses (Gramineae) were over-represented, thus giving a higher percentage. However, the sparseness of the pollen count is caused by the very small size of the sample and the resultant lack of total spores and pollen, but this does not detract from the conclusion that the soil sample comes from a grassland environment.|
As can be calculated from the above list, up to 84% of the total pollen count consists of pollen from Gramineae (grasses) and Compositae (daisies). Other plants rarely form more than 4% of the count. The samples do show some variation, but no more than is to be expected from mud collected from stock pens, where ground is constantly stirred up and often muddied by animals brought in from outside the immediate area. What the samples do show are that they are all derived from a grassland environment and that both native and exotic plants grew in the area, but not in any great abundance and not very close to the stock pens. The variations that appear in the percentages of the more infrequent plants are in part caused by the very low counts done at the time, ranging from 137 to 210 page 8 spores and pollen. It was not considered profitable to count further since the demonstration of a grassland environment would not change with a higher count. Another reason for the variation is simply that they reflect pollen influx over different seasons in the year in one area, and influxes of soil from outside the immediate environment. However, in spite of the variation there was no evidence to suggest that the samples from the stolen antler and wool bale sack could have come from any area other than Ohinepaka Station.
A few spores and pollen were not idenfified, as these were from exotic (not native) plants not represented in our spore/pollen reference collection. However, this does not negate the fact that the samples, within the limits of the palynological tehnique, were very similar, and all came from the same environment.
A point to be stressed about the sample from the base of the antler found in possession of the suspect is that the mud sample was mixed with blood. This indicated that the spores and pollen in the mud and the blood arrived on the antlers at the same time, while the blood was still wet. This time must have been immediately after the antlers were cut. and since the mud contained pollen from a grassland environment they could not have been taken from free ranging deer in either native or exotic forest or bush.
There are one or two intereting aspects of the plants identified. The sample from the inside of the stolen wool bale sack contained pollen that could only have come from soil or rocks greater than one million years old. This sample contained pollen of Casuarina (she-oak, a plant now growing in Australia and Polynesia), Nothofagus brassi beech (large leafed beech growing today in New Caledonia), and fossil Proteaceae (proteas). This distinct difference from the other samples could be explained by the fact that the wool bale sack would have been used a number of times and had in the past carried material containing mud or rock fragments containing extinct pollen types. These pollen types were of a different colour from the more recent grains, which were light in colour and better preserved.
Another feature was the variety of liverwort spores identified from the stock yards and the mud/blood sample from the base of the antler found in possession of the suspect. Such a variety is unlikely from a sample taken from a clearing in bush or scrub. The plants involved suggested a permanently damp and muddy situation, such as stock pens usually are, although a similar situation would occur on muddy banks of streams. Inspection of the stock pens confirmed that they were muddy and that liverworts were growing around the fence lines. There was also a number of native and exotic plants growing in the area whose pollen was represented in the soil samples.
Finally, pollen of a number of plants occurred that would be unexpected in an upland forest or bush situation. For instance, Salix (willow) is common around streams and on farms; Juglans (walnuts) is often found on abandoned farms and settlements now overgrown, but still is unlikely in upland areas. The pollen of native plants identified from the samples are wide ranging types that could well have come from nearby native forest, but the low abundance shows that the forest was a considerable distance away. These pollen types usually overwhelm pollen from herbaceous plants, which do not produce pollen in the abundance that forest trees do.
After five hours of deliberation the jury found the suspect guilty of receiving the deer velvet, and since the police could not present any evidence as to who had committed the initial theft, that charge was dropped. The judge in his summing page 9 up laid especial weight upon the forensic evidence that had indicated that the stolen antlers and wool bale sack had all come from a grassland environment and that no countering evidence had been produced to suggest that the source area of all soil samples examined was other than Ohinepaka Station.
This is but one case in which palynology has assisted a jury in coming to a verdict in a criminal action in New Zealand. In most situations the evidence is circumstantial, either showing that a suspect's alibi is highly improbable, or showing that a suspect, or something connected with a suspect, came from an environment similar to that in which a crime had been committed (Mildenhall, in press). Not all the palynological evidence presented above is produced in court in the form of verbal testimony. Palynological data by their very volume present problems of presentation, and concentration on the environment that the samples come from, and on certain key plants, relieves the palynologist of having to explain insignificant differences between pollen assemblages examined. All data are, however, available to both defence and prosecution and this allows the material to be challenged, since data a palynologist thinks are insignificant, may turn out to have a significance not previously realised. The defence can also get alternative opinions based on the list of identifications and pollen counts. It should be realised that only the list of plants and the counts represent factual data; the rest is interpretation and opinion and as such can and should be challenged.
The various drafts of this paper were read by Geoff Gregory, Ian Raine, David Skinner and Graeme Wilson (New Zealand Geological Survey), to whom I am most grateful. Thanks are extended to Bruce Sampson (School of Biological Sciences, Victoria Univertsity of Wellington) for his encouragement in this project.
Erdtman, G. 1969: Handbook of palynology. An introduction to the study of pollen grains and spores. Hafner Publishing Company, New York. 486 pp.
Leroi-Gourhan, A. 1975: The flowers found with Shanidar IV, a Neanderthal burial in Iraq. Science 190: 443-451.
Mildenhall, D.C. 1982: Forensic palynology, Geological Society of New Zealand newsletter 58: 25.
Mildenhall, D.C. (in press): Forensic palynology in New Zealand. Proceedings of the 7th International Palynological Congress, Brisbane, 28 August-3 September, 1988.
Skinner, D.N.B.; Challis, G.A.; Mildenhall, D.C. and Watters, W.A. 1988: Of Rainbow Warriors, deer antlers, platinum, and other things: forensic science in New Zealand Geological Survey. New Zealand Geological Survey report G130: 13 pp.
Stead, I.M.; Bourke, J.B. and Brothwell, D. (eds) 1986: Lindow man: the body in the bog. British Museum Publications, London, 208 pp.page 10 page 11
Fig. 1Photomicrograph ofCannabis (cannabis). These pollen grains are often found associated with hashish (cannabis oil and resin), in soils close to groves of flowering cannabis, and on the clothes of people cultivating cannabis plants. X 1000.
Fig. 2. Photomicrograph of Artemisia (sage brush). The pollen grains are often found associated with imported hashish. X 1000.
Fig. 3. Photomicrograph of Impatiens (balsam or water fuchsia). These pollen types suggest a tropical or northern hemisphere source for imported drugs. X1000.
Fig. 4. Photomicrograph of Foeniculum (fennel). A pollen type found regularly in forensic palynological samples. X 1000.
Fig. 5. Photomicrograph of Salix (willow). A pollen type found regularly in forensic palynological samples. X 1000.
Fig. 6. Photomicrograph of Ribes (gooseberry). These pollen types were found in surface samples around and underneath a body, but were not found on mud on top of the body. This, along with other evidence, proved that the mud on the body came from some other source, and that the body, along with the mud, had been taken to the site after death. X 1000.
Fig. 7. Photomicrograph of Alnus (alder). These pollen types are often found in drugs and other items imported from the northern hemisphere. X 1000.
Fig. 8. Photomicrograph of Eucalyptus (eucalypt). These pollen types are very common in forensic samples. X 1000.
Fig. 9. Photomicrograph of Acacia (wattle). These pollen types are thought to disperse only short distances from the parent plant. Therefore their presence in forensic palynological samples indicates that the tree occurs close by the source of the samples. Such evidence can assist towards sourcing items to particular sites, and this pollen type, along with other evidence, assisted in sourcing the stolen deer velvet to Ohinepaka Station. X 1000.
Fig. 10. Photomicrograph of Juglans (walnut). These pollen types have assisted towards sourcing forensic palynological samples by suggesting that sites lacking in walnut trees could not have been the source. This, along with other evidence, assisted in sourcing the stolen deer velvet to Ohinepaka Station. X 1000.