Planting Evidence

A larger overlap than you might think exists between plant science and crime investigation. This confluence was suggested at the recent Killer Nashville conference by Jane Bock, Professor Emeritus in the University of Colorado’s Department of Ecology and Evolutionary Biology.

For writers, this field opens new possibilities for developing clues and those arcane hooks that make a story unique. Clues based on plant science can be crucial to a case: Ask Bruno Richard Hauptmann, who was executed for the kidnapping and murder of the Lindbergh baby largely on evidence related to the wood used to construct a homemade ladder (still controversial, and there are true believers on both sides).

Botanists get involved in crime investigations for any number of reasons: they’re asked to identify plant-based controlled substances; they’re asked to identify plant material found on a corpse’s body or clothing or at the crime scene; they’re asked to help identify plant cells (from fruits, vegetables, seeds) found inside a body, in the g.i. tract. This reveals not only what the victim ate, but whether it was harmful or poisonous. Where in the gastrointestinal tract the cells are found can help determine time-of-death. If they’re still in the stomach, death probably occurred no more than two hours after a meal. If they’ve moved on, well, let’s not discuss it.

Forensic botanists also are expected to know what grows where and when. A flower out of season suggests it came from somewhere else. (An episode of the BBC mystery Vera used this type of clue.) Do a suspect’s skin, fingernails, clothing, shoes, vehicle, or home contain traces of the same plant material found on the victim? The more anomalous the material is to when and where it’s found, the more likely suspect and victim are connected.

Dr. Bock and her U of C-Boulder colleague, David Norris, published a textbook on this topic in 2012, based on the approximately 50 cases they worked on. Each has served as an expert witness for both the prosecution and the defense in homicide cases. If you want to dig into this further, other more recent resources continue to pursue these seeds of crime.

Further Reading:
Murder Most Florid, by Dr. Mark Spencer (2019)
Plants and Crime: A Green Mystique Forensic Mystery Companion by Alan Graham (2021)