Interpreting Stains

Within the field of forensic anthropology, a primary goal for investigators is the estimation of a decedent’s post-mortem interval (PMI). Given its importance, numerous unique techniques exist to aid in accurate and precise PMI determinations. However, very few of these methods thoroughly account for the timeline upon which osteologic material becomes stained by its depositional environment. The organic structure of bone allows for a unique pattern of discolouration, but it can be difficult to interpret these properly. In order to discuss the widest array of discolouring factors, the following comprises results from varied individual studies, with the specifics of each process briefly described in order to present a wider overview of each factor. Four key headings allow an organized approach to the material—(i) Soil Contents, (ii) Atmospheric Processes, (iii) Human Traces, and (iv) Nefarious Acts—with each heading discussing three common sub-discolourants. Stains arise either by natural or nefarious means, varying drastically by geographical location and climate, producing a range of observable results. The analysis concludes with an integrated discussion of the factors detailed herein, to ultimately evaluate the question of whether or not discolouration can be utilized as a reliable PMI-estimation methodology.