Source: Chemistry World through Forensic News
Evidence left at the scene of a crime can be in many different forms including fingerprints, blood, fibers, paint chips and hair. It is the role of forensic scientists to analyze this evidence, which is often only present in very small amounts, to help find the culprits. In previous research, blood has been used to identify gender and ethnicity, but a problem with this is that blood can deteriorate quickly and can easily be destroyed or contaminated.
Hair, on the other hand, is very stable. Most elements in hair originate from sweat secretions, and their composition alters with diet, ethnicity, gender, the environment and working conditions.