Forensic stable isotope signatures: Comparing, geo-locating, detecting linkage

Stable isotope signatures or profiles of physical evidence such as illicit drugs, explosives or human tissue provide information on source, origin, even sample history not obtainable by traditionally applied analytical techniques of forensic chemistry. The discriminatory power, calculated as random match probability, of multivariate stable isotope signatures able to distinguish two cocaine samples from different regions in Colombia can range from one in tens of thousands to one in several million if based on the stable isotope abundances of carbon, nitrogen and hydrogen or carbon, nitrogen, hydrogen and oxygen, respectively. Stable isotope signatures of physical evidence have therefore at the very least great potential to provide invaluable forensic intelligence for intelligence led policing. They may even be of great evidentiary value, especially if corroborated by results from independent analytical techniques. This review aims to offer a glimpse into the fascinating world of forensic stable isotope analysis by discussing the various levels of information stable isotope signatures can provide. For reasons easily appreciated, only a select few instances of its application to criminal investigations have been reported in scientific journals thus far. The various applications of this technique presented in this review are therefore predominantly taken from peer-reviewed work published in scientific books and journals. This article is categorized under: Forensic Biology > Interpretation of Biological Evidence Forensic Chemistry and Trace Evidence > Explosive Analysis Toxicology > Drug Analysis