Forensic botany refers to the use of plant materials to help solve crimes or resolve other legal problems. With the greater complexity and technological sophistication of evidence now being presented, law enforcement and the courts have become increasingly more aware of how evidence from botany can provide important supporting, sometimes crucial, evidence in criminal or civil cases. Because plant remains are found almost everywhere, they may occur as trace evidence at a crime scene in the form of macroscopic pieces of wood or charcoal, seeds, fruits, leaves, twigs, flowers; as microscopic air-borne pollen or spores, plant trichomes, plant cells in stomach contents; or as DNA in plant fragments. The morphological and molecular diversity expressed in the over 300,000 plant species and the frequently specialized ecological parameters of plants allow investigators in criminal cases to identify plant parts, and from the identification gather such useful information as the geographical location or season in which a crime took place, whether a body has been moved or how long it might have been buried, and whether a suspect was present at a crime scene.
In one of the earliest and most famous cases in which botanical evidence was accepted as valid scientific evidence, the kidnapper of the child of aviation hero Charles Lindbergh was unquestionably linked to the crime by information from plant anatomy. Wood from the ladder used in the kidnapping was matched by species and by identical structural pattern to flooring cut from the attic of the kidnapper. More recently, several criminal and civil cases have depended on identification of plants from their pollen. Suspects in violent crimes have been directly linked to a crime scene by a specific pollen type which was unseen and unknown by them to be present on their clothing. The U. S. Department of Agriculture has relied on pollen identification to determine the true source of commercial honey, when valuable specialty or domestic honey is suspected of having been replaced or adulterated by lower grade foreign sources. Additional applications of forensic botany in criminal investigations may be found in “Forensic Botany”, Heather M. Coyle, Ed., CRC Press, Boca Raton, FL, 2005 and in papers from a symposium on Forensic Botany in Journal of Forensic Sciences 42 (3), May 1997.
Analysis of plant materials for forensic purposes requires expertise in one or more of several plant science subdisciplines such as systematics, anatomy, palynology, ecology, molecular biology, or plant chemistry. Assessment of evidence also frequently requires access to extensive reference collections from herbaria; palynological, anatomical, or morphological slide collections; or other forms of comparative materials. For these reasons, investigative laboratories have generally relied on botanists who are employed by universities, museums, or botanical gardens for answers to very specific questions and have not typically employed plant scientists in laboratory positions. The widening use of plant DNA in forensics, first applied in a criminal investigation in 1992, has now raised the opportunities for employment of graduates with bachelors level and higher degrees who have experience in molecular plant biology. Awareness of the importance of other kinds of botanical evidence is growing, too, and although positions in federal, state, and local crime scene laboratories still do not specifically include a “forensic botanist”, laboratories do seek broadly trained undergraduates and graduates in botany and biology who are open to further specialized on-the-job instruction. Increasingly, too, private companies are specializing in forensic assessments and some professional botanists have moved from universities to establish these companies or to work in them.
Forensic laboratories advise students interested in botanical trace evidence analysis to begin with a solid undergraduate degree in botany or biology. Useful internet sources of information are www.FBI.gov which lists employment opportunities and summer student volunteer internships and www.bls.gov under Science Technicians. Other government agencies that hire forensic analysts are the federal U.S. Drug Enforcement Administration (DEA) and Bureau of Alcohol, Tobacco, Firearms, and Explosives; and forensic laboratories of the state police and the local county sheriff’s office. As with any career search, learning about the work by speaking with people at places that do the work that interests you is an early step in planning your future education and employment.
Shirley Graham, Kent State University