Palynology applied to Forensic Sciences: principles and examples

Forensic Palynology is still often considered a quite new discipline but its first applications go back to the ’50s (Erdtman, 1969). Since then, and particularly in the last years, the study of pollen and spores from crime scenes and in criminalistic cases has known an endless development (Bryant et al., 1996; Mildhenhall et al., 2006a). Pollen evidence was frequently reported as an important witness to criminalistic case solving, and a versatile investigation tool in many offences such as homicides (Milne, 1998), human remain concealment (Szibor et al., 1998), kidnapping (Mariotti Lippi and Mercuri, in press), robbing (Mildenhall, 1998), drug enforcement (Mildhenhall et al., 2006b). "Pollen fingerprint" is specific for every kind of crime and obtainable by both sampling on the body and in the environment. Forensic Palynology is part of Forensic Botany, and would be managed by a botanist (Miller Coyle, 2005). It has roots in Palynology, with which it shares both the object of study (pollen, spores plus other palynomorphs), and the basic principles for sampling, and sample processing, analysis and interpretation. However, sampling procedure and processing may require specific behavioural rules and different treatments to isolate and fix pollen from diverse substrata and in different situations. Main aim of Forensic Palynology is to answer the questions of “where?” and “when?” a crime has been made.Records reflect the environment where the parent plants and fungi live, and more various and abundant are the pollen records, more precise and unambiguous will be the environmental picture. If a significant number of records is found, the palynologist is able to assess the pollen spectra of the case. Pollen types with their percentage (or concentration) values can be grouped in groupings useful for interpretation (for example, trees, shrubs, herbs, aquatics, exotics, cultivated plants, etc.). The pollen spectrum, obtained for example from the body of a suspected or victim, will bring pollen marks of the environment where the person has passed through, thus giving useful and sometimes key information for crime investigation. Less frequently, it also reveals the season of death.At the state of the art, the interest of police forces and investigators for this science is rapidly increasing, and interdisciplinary workshops and conferences dealing with Forensic Palynology are more frequent. But the search for pollen evidence in criminal cases is still far to be routinely applied. Some problems are main obstacle to the real development of this science: 1) Palynologists would be involved in police investigations since the first phase, but actually they were commonly excluded by key procedures such as the inspection of the crime scene. 2) It should be give more possibility to experts to disseminate the sampling and treatment modalities, and the results obtained from pollen analyses in cases that were resolved; also, scientific papers must be published. 3) Specific experimental studies should be made to simulate and reproduce false-criminal events, and to observe the pollen spectra obtained. Scientific papers on actual and experimental cases will encourage more scientists to carry out these analyses, and will improve the set of reference data useful for reasonable comparative interpretations.Some recent meetings on Forensic Palynology have notably improved the interest of experts and the exchange of experiences. The continuative involving in forensic cases for pollen sampling and analysis could drive interpretation to finer levels. In this paper, some examples of pollen clues which had helped the investigations are reported, such as the strange case of the ‘yellow rains’, the silent marker of displacements and travels, the invisible witness of aggressions and robberies. Moreover, how the method assessed from other applicative fields of palynology, such as archaeobotany and melissopalynology, is useful to give a contribution to the forensic sciences is discussed. ReferencesBryant V.M., Jones J.G., Mildenhall D.C. (1996) Chapter 23G Studies in forensic palynology. In Jansonius J., Mc Gregor DC (Eds) Palynology: principles and applications. American Association of Stratigraphic Palynologists Foundation, pp 957-959.Erdtman G. (1969) Handbook of Palynology. New York, Hafner Publishing Co.Mariotti Lippi M., Mercuri A.M. (in press) Palynological analyses applied to a case of kidnapping in Italy. GEA-Giornale Europeo di Aerobiologia, Atti Workshop ‘Forensic Palynology in Italy’ (Roma, 11 settembre 2007).Mildenhall D.C. (1998) Deer velvet and palynology: an example of the use of forensic palynology in New Zealand. Tuatara 30: 1-11.Mildenhall D.C., Wiltshire P.E.J., Bryant V.M. (2206a) Forensic palynology. Forensic Science International 163: 161-162.Mildenhall D.C., Wiltshire P.E.J., Bryant V.M. (2006b) Forensic palynology: Why do it and how it works. Forensic Science International 163: 163-172.Miller Coyle H. (2005) Forensic Botany. London, CRC Press.Milne L. (1998) Forensic palynology. Pollen and spores, Nature's fingerprints of plants http://science.uniserve.edu.au/faces/milne/milne.html Szibor R., Schubert C., Schoning R (1998) Pollen analysis reveals murder season. Nature 395: 449-450.