Identification of Human Decomposition VOCs in Concrete Evidence Using HS-SPME GC–MS

Various volatile organic compounds (VOCs) released during the process of human decomposition are chemically diverse and may provide forensic evidence revealing the prior presence of a corpse. In July 2023, the Michigan City Police Department received a report from an individual claiming to have murdered his roommate and stored the body in a basement cellar for 57 days before dismemberment and disposal. Concrete core samples from the basement were analyzed by researchers at Indiana University, Indianapolis, and The Michigan City Police Department using headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME GC–MS). A paper based on this analysis was published in the Journal of Forensic Sciences. (1)

Common VOC profiles associated with human remains have been documented through extensive research, although definitive human-specific markers remain elusive. (2-4) Despite this limitation, however, the detection of these VOCs can strongly substantiate investigative hypotheses concerning decomposition events. As previous forensic VOC studies have primarily utilized soil or fabric substrates, using HS-SPME GC–MS for the analysis of concrete, according to the authors of the study, was “particularly novel.” (1)

In August 2022, John Hallett confessed to murdering and dismembering his disabled roommate, Paul Gonzales, in Michigan City in November 2017, though the body was never recovered. Investigators found corroborating evidence: Gonzales’s digital and financial activity ceased in 2017, he stopped medical care, and welfare checks raised concerns. A cadaver canine alerted in the basement Hallett described, and presumptive testing indicated the presence of blood, supporting the confession. (1)

Three concrete samples analyzed by the investigators contained six VOCs that are known to originate from the decomposition process, which led to the conclusion that the decomposing body of someone or something was present in the room for enough time for the decomposition VOCs to collect on, in, and under the floor. (1)

“This case,” write the authors of the study (1), “represents the first successful legal introduction of VOC analysis evidence from concrete substrates within the State of Indiana.”

The identification of multiple characteristic VOCs provided evidence substantial enough to support the occurrence of prolonged decomposition at the Michigan City crime scene. The wording of the final laboratory report included the following: “Taken together, four items contained nine VOCs that are known to originate from the decomposition process. This leads to the conclusion that the decomposing body of someone (or something) was present in the room for enough time for the decomposition VOCs to collect on, in, and under the floor.” (1)

This forensic evidence ultimately contributed to the suspect's conviction and underscored the critical role that scientifically validated chemical analyses of VOCs can have in homicide investigations. (1)

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References

1. Hecker, A.; Painter, A.; Goodpaster, J. The Scent of Death: A Case Study for Volatile Markers of Decomposition on a Concrete Floor. J Forensic Sci. 2026. DOI: 10.1111/1556-4029.70271
2. Vass, A. A. (2001). Beyond the Grave-Understanding Human Decomposition. Microbiology Today 2001, 28, 190–193. https://www.academia.dk/BiologiskAntropologi/Tafonomi/PDF/ArpadVass_2001.pdf
3. Verheggen, F.; Perrault, K. A.; Megido, R. C. et al. The Odor of Death: An Overview of Current Knowledge on Characterization and Applications. Bioscience 2017, 67 (7), 600–613. DOI: 10.1093/biosci/bix046
4. Percival, S. L. Microbiology and Aging; Humana Press; 2009; p. 313–334.