Managing the forensic examination of human hairs in contemporary forensic practice

Abstract

The purpose of this review is to critically examine the current status of the forensic examination of hairs in the context of previous critical commentary and the recent report of the Presidents’ Council of Advisors on Science and Technology (PCAST). The review looks at the historical development of hair examination in the last 100 years as it has been influenced by broader scientific developments that have seen the emergence of analytical sciences, including electrophoresis, and serology replaced by DNA analysis. A criminalistics perspective to the forensic management of hairs is presented that combines the benefits of microscopic observation and DNA analysis into a holistic case management approach. The author provides a personal view of, and commentary on, the approach used by FBI examiners, and others, to the microscopic examination of hairs pre the advent of DNA and argues that this is no longer relevant to current practice provided that examinations are conducted by appropriately science qualified examiners who properly record systematically and in detail their observations. Finally, the review looks to the future for the forensic examination of hairs in contemporary forensic practice.

keywords:

• Hair examination
• microscopy
• criminalistics
• Nuclear and mitochondrial DNA
• bias

Acknowledgements

I wish to thank my colleagues at UC, Dennis McNevin and Michelle Gahan for their useful comments on this paper and my co-researcher Elizabeth Brooks who has shared the last 10 years of my hair journey.