Post-mortem interval estimation using volatile fatty acids from beneath pig carcasses decomposing on common New Zealand soils

Abstract

Estimation of the post-mortem interval (PMI) was investigated by analysing the presence and amount of volatile fatty acids (VFAs) in soil solution over two decomposition periods. Soil solution was extracted from soil samples collected from beneath decomposing domestic pig carcasses, Sus scrofa L.., and analysed for VFAs using GC/MS. Three carcasses were studied on soil during mid-winter to late-spring and six carcasses on soil and sand during mid-spring to early-summer. Also investigated was the effect of storage of samples on VFA presence. Seven VFAs of significance were detected. The effect of season, soil type and storage was inconclusive due to response variability. A relationship between the post-mortem interval and the ratio of VFAs was not observed in pigs. It is concluded that the complexities of the decomposition process and influencing environmental factors are too variable for the study of VFAs to be used for PMI estimation in forensic casework.