Chemical Detection of Non-Volatile and Semi-Volatile Decomposition Markers from Clandestine Gravesites

Over 134,000 individuals went missing last year of which 1,340 were not found at
all, the number of people who disappear due to a homicide is indeterminate as a
victim’s body is required to prove a homicide unequivocally. A variety of search
methodologies are applied to locate clandestine graves ranging from victim recovery
dogs to geophysics. It has been highlighted that the current search methodologies
to locate clandestine gravesites are not always successful and require a significant
amount of time and public funding. This study sought therefore to detect the
non-volatile and semi-volatile decomposition products from soil and water samples
which could aid the detection of clandestine gravesites and lead to the development
of field based chemical tests to speed up the search process.
Three novel alternative analytical methodologies have been developed in order to
allow for the detection of non-volatile and semi-volatile decomposition products in
in soil and water samples from a simulated grave environment and actual casework
samples. The first methodology utilised high performance liquid chromatography
(HPLC), which indicated that over 100 decomposition specific chemicals were
detected in the leachate samples. This highlighted the potential for using HPLC as
an alternative method for the detection of non-volatile and semi-volatile
decomposition products from soil-water samples. The second methodology
developed utilised ion chromatography (IC) and has proven its capabilities for the
analysis of forensic samples by differentiating between the soil samples provided
and highlighting areas of interest. The third and final methodology developed utilised
derivatisation gas chromatography (GC) for the targeted analysis of biogenic
amines putrescine, cadaverine and methylamine. A highly specific methodology
was developed for the analysis of primary amines in soil-water samples following
simultaneous derivatisation of these amines using pentafluorobenazaldehyde.
These amines were detected in the leachate samples from 28 to 669 days post
burial, which far exceeded other longevity studies conducted within the discipline of
forensic taphonomy. Putrescine was detected in the casework samples where the
individual went missing more than 15 years ago and therefore highlights the
suitability of the established methodology to aid in the search and recovery process
of clandestine gravesites. Utilisation of these methodologies will lead to further
identification of the key decomposition products produced during the human
decomposition process and allows for the development of field-based chemical