What if fungal spores and pollen grains could reveal the secrets of clandestine graves? That is the hypothesis explored by an international team of researchers in Colombia, who conducted a pioneering experiment combining mycology and palynology in a forensic context.
A biological approach to detecting illegal graves
In an experimental project carried out in Bogotá, two graves simulating clandestine burials were dug — one empty, the other containing a pig cadaver (a standard human body substitute in forensic science). Soil samples were collected and analyzed at different depths to study fungal and pollen communities composition. The aim of the study was to determine whether decomposed organic remains alter the soil’s microbial and plant-based communities, and whether these biological signatures could serve as spatial and temporal indicators in criminal investigations.
Revealing fungal and pollen richness
The results showed that soil from the pits containing a carcass exhibits greater fungal richness (higher species diversity), notably with species such as Fusarium oxysporum and Paecilomyces, whose frequency increased in the presence of decomposition. These organisms, capable of degrading nitrogen-rich compounds such as keratin, could serve as indicators of buried organic remains.
Fungal structures of Fusarium oxysporum observed under optical microscopy.
A and B: macroconidia; C: chlamydospores. © David Esteban Duarte-Alvarado
On the palynology side, pollen grains identified at 50 cm depth—including Borago officinalis, Poa sp., and Croton sonderianus—are typical of the dry season. In contrast, the pollens found at 30 cm correspond to the rainy season. This stratified distribution could allow investigators to estimate the burial and exhumation periods with greater accuracy.
Integrating soil biology into criminal investigations
This study is the first to provide experimental data on mycology and palynology in an equatorial tropical context, a field largely unexplored in forensic science until now. It paves the way for a more systematic integration of these disciplines in crime scene investigations involving clandestine graves or the search for buried remains. While preliminary, the findings demonstrate the value of biological approaches as a complement to conventional forensic methods especially in regions where climatic conditions influence decomposition dynamics.
Conclusion
This study is part of a broader research effort into biological indicators left by buried bodies. After trees and roots that can signal underground anomalies, it is now fungi and pollen that emerge as silent witnesses of clandestine deaths. This microbiological approach expands the toolkit of forensic archaeology, as practiced by experts such as those from the French Gendarmerie. By combining invisible biological traces with conventional excavation and stratigraphic analysis techniques, it enables a more precise reading of the soil—and the criminal stories it may conceal.
Reference :
Tranchida, M. C., et al. (2025). Mycology and palynology: Preliminary results in a forensic experimental laboratory in Colombia, South America. Journal of Forensic Sciences.
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