Chemical Analysis of Processed Human Hair Extensions for Use in Forensic Casework
With the increasing use of hair extensions, it is possible that a hair sample discovered at a crime scene may be a processed human hair extension and have no physical or genetic connection to the individual wearing the hair extensions. This can be misleading in an investigation and result in a misuse of time and resources. Being able to identify a hair as a processed human hair extension may be valuable in determining its evidentiary value. This research utilized ultraviolet-visible spectroscopy, gas chromatography/mass spectrometry, and nuclear magnetic resonance spectroscopy to determine whether a chemical difference was present between natural human head hair and processed human hair extensions. Three different hair extension brands and five different natural human hair samples were used in this research. Multiple organic solid liquid extractions were completed using methanol, hexane, 1-octanol, Colorist SecretsTM Hair Color Remover, and chloroform-d. Results indicated there is a chemical difference between processed human hair extensions and natural human head hair as observed in spectra on the UV-Vis, GC/MS, and NMR. Peaks were present in the processed human hair extensions that were not present in the control natural human head hair samples. This research is significant because it allows for the chemical identification of processed human hair extensions which may help in determining if the hair has probative value in a forensic case.
Fingerprints and Ancestry: Is it all in the Details?
Research assessed if ancestry can be determined based on fingerprint characteristics. Ancestral backgrounds analyzed included individuals of European, African, Asian, Hispanic, and Native American descent. The results of this study provided important insights into the frequencies and likelihood of certain fingerprint patterns and minutia coming from specific ancestral groups. Important findings included:
- Sex is not a significant predictor of pattern type whereas ancestry is a significant predictor of pattern type.
- Minutiae types cannot predict sex, but are be useful in predicting some ancestries,
- The Native American ancestral group had the highest pattern frequency of whorls at 47.5%.
- The African descent group had statistically more bifurcations than all other population groups in the study.
- The frequency of arch patterns for European descendants was double the frequency for arch patterns within African descendants.
While this is a novel concept in forensic science, it could be an investigative aid used to include and exclude potential suspects based on ancestry or as corroborative evidence in a case aiding law enforcement in combatting and identifying criminal offenders. The results of this study, however, can only be used as a forensic tool for potentially limiting suspects and would not be admissible in court or stand alone as evidence as this could set dangerous precedents such as profiling behaviors within law enforcement.
Driving under the influence of drugs (DUID) cases represent the largest portion of cases handled in most forensic toxicology laboratories. Blood is a commonly used specimen and is often analyzed using gas chromatography-mass spectrometry (GC/MS). A common extraction for this method requires two milliliters of blood. Currently, the Oklahoma State Bureau of Investigation (OSBI) Laboratory operates LC-based extractions which require 250 to 500 microliters of sample to complete, but these are limited to specific drug classes. A general drug screen for forty drugs has been developed and validated using 250 microliters of blood. An additional validation has been completed which required 100 microliters of sample to confirm the presence of thirty-nine drugs.
Danielle Ross-Carr -2017
The widespread conversion of drunk drivers to drugged drivers means that forensic laboratories have had to drastically increase the scope of their DUI/DUID testing. This increased scope has caused an expansion of the types of laboratory instrumentation used. In an attempt to identify the instrument best suited for DUI/DUID casework, an in-depth analysis was performed that evaluated presently-applied techniques as well as emerging techniques.
Kara Sitton – 2020