CSI: Botany – Using Plants And Forensic Science To Solve Crimes

51qxFlFAUaLForensic Botany?

In the last few decades, forensic science has seen a large growth in research and application. This site that profiles forensic science college programs does a decent job of explaining how the forensic science profession operates. While there may be fewer car explosions and shoot-outs than on television, it’s still a very cool field of science. Forensics has worked its way into other disciplines of study, including nursing, accounting and psychology.

What do the Lindbergh baby kidnapping in 1935, a murder in the Arizona desert in 1992, the assault of a young woman in New Zealand in 1997, and the infamous Soham murders in 2002 all have in common?

They were all solved, at least in part, by forensic evidence from plants. (To find out how, please see below.)

Recent musings by Dr. Nigel Chaffey (see Ref. 1 below) regarding the apparent paucity of plant-based evidence in most episodes of the ever-popular CSI (Crime Scene Investigation) TV programs prompted me to investigate the subject, namely, Forensic Botany.

I must say that I was a bit surprised by what I found out.

First off, yes, indeed, there is a literature devoted to the subject (see Ref. 2 below) – even entire books (see right, e.g.), with more on the way.

So, apparently, there is a burgeoning interest in forensic botany.

Some creative teachers have even incorporated forensic botany as an alternative to the traditional lab practical used to assess students’ skills and knowledge in plant cell biology and anatomy. (see Ref 3 below, e.g.)

However, it seems that efforts to solve crimes by employing such botanical evidence is under-utilized. One reason I found often-cited for this is that there are insufficient numbers of people with a knowledge of plant taxonomy, plant anatomy, palynology, etc., qualified to expertly assist in such investigations. Also, “In great part, the failure to incorporate botanical evidence in investigations is due to lack of knowledge about plants by personnel who study crime scenes and so fail to collect it.” (from: Crime Scene Botanicals)

Briefly, What Is Forensic Botany?

From Wikipedia: “Forensic botanists look to plant life in order to gain information regarding possible crimes. Leaves, seeds and pollen found either on a body or at the scene of a crime can offer valuable information regarding the timescales of a crime and also if the body has been moved between two or more different locations. The forensic study of pollen is known as forensic palynology and can often produce specific findings of location of death, decomposition and time of year.

While the field of forensic botany encompasses a variety of sub-disciplines ranging from plant taxonomy to palynology, applications involving DNA profiling of plant material have been relatively limited.

Palo Verde A somewhat well-known case involved seed pods of the Palo Verde tree (Cercidium sp.) recovered from the pick-up truck of a suspect.

Randomly Amplified Polymorphic DNA (RAPD) genetic profiling was used to link the seed pods to an individual tree found at the murder site (Please see Ref 4 below).

Recent advances in DNA fingerprinting technology (see Refs 5 & 6, e.g.) have shown that this technique may be a valuable resource for forensic applications, primarily to provide physical evidence that links plant materials to live plants at or near crime scenes.

Perhaps a more common use of this technology will be to identify individual plants, plant species, and plant populations and provide this as legal evidence for court proceedings against illegal loggers, drug dealers, and plant patent infringers.

Botanical Witnesses For The Prosecution

How was plant-based evidence used to help solve the cases mentioned at the beginning of this post?

In the Lindbergh kidnapping case, Dr. Arthur Koehler, an expert on wood anatomy and identification, provided dendrological evidence that a ladder found at the scene of the crime belonged to the chief suspect, Bruno Richard Hauptmann. The wood anatomical evidence ultimately was one of the most incriminating and unshakable pieces of evidence that led to Hauptmann’s conviction and his eventual electrocution for the kidnapping.

In the murder case of Denise Johnson in 1992, whose body was found in the desert near Phoenix, Arizona, forensic botanical evidence linked the murderer’s pickup truck to the crime scene. As previously mentioned, this was the first case in which DNA analysis was used to match the “tree fingerprints” of an individual tree at the murder site with seed pods from the tree in the bed of the suspect’s truck. (Please see Ref 4 below for more about this story.)

In the New Zealand case, unusual fungal spores and pollen from soil at the scene of the assault was shown to match those found in dirt-stains on the suspect’s clothes. This pollen and spore evidence was presented at the trial, the suspect was convicted, and he was given an 8-year prison sentence.

PollenAnd, finally, it was Patricia Wiltshire, “the queen of forensic science” (see Selected Links below), who established that pollen from the murderer’s shoes and his car exactly matched the type found in the ditch near where the victims’ bodies had been discovered.

Selected Links:

If one “Googles” the phrase “forensic botany”, quite a few links pop up. After exploring many of these links, I found the following especially interesting and informative (to me, at least):

Crime Scene Botanicals An excerpt from Plant Science Bulletin, Vol. 52, #3, Fall 2006 (PDF) – This is a very informative and comprehensive resource. (My hat’s off to the Botanical Society of America for making this publication freely available online.)

Forensic botany (This Forensic Botany site was created in 2002 by Jennifer Van Dommelen as a project in the Web Literacy For the Natural Sciences class at Dalhousie University, Halifax, Canada.)

Forensic Botany and Ecology by L. Labate, J. Lee & S. Kim – A PowerPoint slideshow nicely introducing the subjects, with references. PowerPoint (PPT) File (Please Note: Clicking on link may trigger download of a 7MB PPT file.)

Another PowerPoint slideshow introducing Forensic Botany (looks like a class project): PPT Quick View – This link will take you to the PowerPoint slideshow at Google docs.

Famous Forensic Botanist: Here’s a profile of Britain’s foremost forensic botanist Patricia Wiltshire.

Want to take a college course in Forensic Botany? Here you go: Forensic Botany offered by The University of Oklahoma Biological Station, taught by Dr. Adam Ryburn.

…or a career in forensic botany?

References

1. Chaffey, N. (2011) “Plant Cuttings: Forensic botany collections.” Annals of Botany, Vol. 109, pp. v-vii. (Full Text)

2. Coyle, H. M., C. Ladd, T. Palmbach, and H. C. Lee (2001) “The Green Revolution: Botanical contributions to forensics and drug enforcement.” Croatian Medical Journal, Vol. 42, pp. 340-345. (PDF)

3. Barratt, N.M (2011) “The case for forensic botany.” The American Biology Teacher, Vol. 73, pp. 414-417. (Full Text – PDF)

4. Yoon, C. K. (1993) “Botanical witness for the prosecution.” Science, Vol. 260, pp. 894-895. (PDF)

5. Craft, K. J., J. D. Owens, and M. V. Ashley (2007) “Application of plant DNA markers in forensic botany: Genetic comparison of Quercus evidence leaves to crime scene trees using microsatellites.” Forensic Science International, Vol. 165, pp. 64–70. (PDF)

6. Tnah, L. H. , et al. (2010) “Forensic DNA profiling of tropical timber species in Peninsular Malaysia.” Forest Ecology and Management, Vol. 259, pp. 1436-1446. (Abstract)

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