Using Carbon,Oxygen, Strontium,and Lead Isotopes in Modern Human Teeth for Forensic Investigations: A Critical Overview Based on Data from Bulgaria

Isotopic data obtained from human remains can provide information about an individual's origin, migration, and diet. We evaluate the usefulness of carbon, oxygen, strontium, and lead isotopes for forensic investigations by comparing data from Bulgarian teeth with data from other regions. Geo‐referencing based on oxygen or strontium isotopes can be misleading due to overlap with other countries in Europe and other continents. Carbon and lead isotopes, in combination with oxygen and strontium isotopes, provide the most useful information for identification of local vs foreigner status. In particular, high‐precision Pb isotopes show a distinct “Bulgarian” range; however, it is possible that individuals from other countries in Eastern Europe and/or central to western Asia could have overlapping isotopic values. Additional high‐precision multi‐isotope data from modern humans from different regions in the world are required to transition from speculative to more quantitative estimation of a geographical place of origin for unidentified human remains.     

The Use of Forensic Tests to Distinguish Blowfly Artifacts from Human Blood,Semen, and Saliva

This study investigated whether routinely used forensic tests can distinguish 3‐day‐old or 2‐week‐old fly artifacts, produced after feeding on human blood, semen, or saliva, from the biological fluid. Hemastix^®, Hemident^?, and Hemascein^? were unable to distinguish blood from artifacts. Hemastix^® returned false positives from negative controls. ABAcard^® Hematrace^® and Hexagon OBTI could distinguish blood from 3‐day‐old artifacts, but not 2‐week‐old artifacts. Phadebas^® and SALIgAE^® were unable to distinguish saliva from artifacts. RSID^?‐Saliva was able to distinguish saliva from 3‐day‐old artifacts, but not 2‐week‐old artifacts. Semen tests Seminal Acid Phosphatase, RSID^?‐Semen, and ABAcard^® p30 were all able to distinguish semen from 3‐day‐old artifacts, but not 2‐week‐old artifacts. The tests investigated cannot be relied upon to distinguish artifacts from biological fluids. However, if an artifact is identified by its morphology, a positive result may indicate which biological fluid the fly consumed, and this knowledge may prove useful for investigators searching for DNA.     

The Effect of Flunitrazepam (Rohypnol®) on the Development of Chrysomya megacephala (Fabricius, 1794) (Diptera: Calliphoridae) and its Implications for Forensic Entomology

This study investigated the potential effects of flunitrazepam (known as “date rape drug”) on the developmental cycle of Chrysomya megacephala, an important forensic species, and their possible implications for the calculation of the PMI. A 1050 C. megacephala eggs were divided into five groups with seven replications each. The eggs were placed on artificial diet prepared with four drug concentrations of flunitrazepam (4, 8, 16, and 32 ng/g), besides the control group (prepared with water). Were evaluated the potential effects on development time, weight gain, and mortality during the cycles. The drug had no significant effect on development time or mortality although it did affect the weight of the pupae and adults (Kruskal–Wallis, p < 0.05). The result can be deduced that the determination of the postmortem interval is not affected.     

Animal Scavenging and Scattering and the Implications for Documenting the Deaths of Undocumented Border Crossers in the Sonoran Desert,

Since 1998, over 5500 people have died while attempting to cross the U.S.–Mexico border without authorization. These deaths have primarily occured in the Arizona desert. Despite the high volume of deaths, little experimental work has been conducted on Sonoran Desert taphonomy. In this study, pig carcasses were used as proxies for human remains and placed in different depositional contexts (i.e., direct sunlight and shade) that replicate typical sites of migrant death. Decomposition was documented through daily site visits, motion-sensitive cameras and GIS mapping, while skeletal preservation was investigated through the collection of the remains and subsequent faunal analysis. Our results suggest that vultures and domestic dogs are underappreciated members of the Sonoran scavenging guild and may disperse skeletal remains and migrant possessions over 25 m from the site of death. The impact of scavengers and the desert environment on the decomposition process has significant implications for estimating death rates and identifying human remains along the Arizona/Mexico border.