Provenancing of unidentified corpses by stable isotope techniques – presentation of case studies

•A reference hair database containing isotope signatures of hydrogen, carbon, nitrogen and sulphur of almost 700 worldwide collected human hair samples has been established for provenancing of unknown individuals.•Isotope signatures of the reference hair samples can be allocated to predefined regional groups by discriminant analyses.•For directly comparing stable isotope data of collagen with those of keratin correction factors has been calculated for adults as well as for newborns.•The incorporation period of the chemical elements into different human body tissues especially for newborns has been elaborated.•The results obtained were applied on real cases of unidentified subjects and successfully used for provenancing of two adults and a newborn's mother.

Stable isotope methods can be used to determine the provenance of unidentified corpses. Body tissue materials such as teeth, bone, hair and nail taken from mortal remains provide information of different time periods of an individuals' life from childhood to death. Tissues of newborns contain provenance information of different time periods during pregnancy of the child's mother.The results of stable isotope analyses of body residues of two adults and a newborn found in Germany between 2010 and 2012 are presented. To determine the geographic origin and movements of unknown individuals, stable isotopes of hydrogen, carbon, nitrogen and sulphur were analysed in hair and bone collagen samples. Amino acid composition and, as a consequence, δ2H, δ13C, δ15N, and δ34S values in human keratin and bone collagen are different. Consequently correction factors were determined to compare isotopic data of bone collagen with those of an extensive worldwide reference hair collection. The isotopic signatures in hair and in bone collagen samples were compared to geographical groups of reference hair samples by canonical discriminant analysis. The results served as the basis for providing provenance constraints for the unidentified persons as requested by the police and prosecution. Ultimately the individuals were identified; hence the isotopic provenance interpretations can be critically evaluated and are shown to be successful.