Unlocking Criminal Cases Through Hair Evidence, Forensic Trichology

Hair holds secrets. Forensic trichology reveals them—uncovering trauma, toxins, or identity through microscopic and DNA analysis, and aiding justice in cases from murder to human trafficking.

Forensic trichology is the scientific study and analysis of human or animal hair in criminal investigations. It involves examining macro-microscopic characteristics, structures, and forms to provide valuable evidence in cases such as homicide, burglary, kidnapping and human trafficking cases, poisoning or drug-related cases, and wildlife crime and animal cruelty cases. Hair analysis can determine species origin, racial background, ethnicity, and whether the hair was forcibly removed. It may also reveal evidence of trauma, drug use, or toxin exposure. It is durable and resistant to decay, making it a reliable form of evidence in forensic contexts.

The scientific examination of hairs began in the early twentieth century, although its potential as forensic evidence was recognised even earlier. In 1910, Victor Balthazard and Marcelle Lambert published "Le Poil de l'Homme et des Animaux", which was one of the first comprehensive studies of human hair in relation to animal hair. Balthazard and Lambert's book described marked structural differences between human and animal hair, which laid the foundation for microscopic hair analysis. Over decades, forensic trichology has produced change from microscopic examinations to DNA analysis, which is now considered a powerful tool used to detect and solve crimes.

One of the notable cases involving forensic trichology was the 1999 PriyadarshaniMattoo case, where forensics conducted microscopy and DNA analysis of hairs collected from the scene of the crime. This scientific evidence added credence to the case against the accused, Santosh Kumar Singh, and helped in the conviction in 2006. Forensic trichology served as corroborative evidence to account for how Singh could have committed the crime. A second notable case was the Delhi gang rape (2012), where forensic trichology partnered with other biological evidence to confirm the presence of the accused in the crime scene. Hair analysis played a crucial role in reconstructing events, aiding in justice for the victim. Alongside other biological evidence, it helped establish the sequence of events, ensuring a fair outcome.

The Indian judicial system has consistently recognised the importance of scientific evidence, including forensic trichology, in the judicial process. Courts acknowledged that analysis of hair would prove extremely useful as corroborative evidence along with other findings in several cases, including the Priyadarshini Mattoo case. By acknowledging the faith worth of such evidence, the judiciary reinforced the complementary role of science and law in achieving justice.

Recent advancements in forensic trichology have transformed it into a cutting-edge discipline. Today, researchers use methods like mitochondrial DNA analysis, which is getting genetic material from hair shafts in the absence of roots. This has come in particularly handy for cold cases where evidence is decades old. The use of mass spectrometry in hair examination is another recent development. It helps in the detection of trace elements, drugs, and toxins in the hair with unparalleled accuracy. Further studies investigated hair proteomics, which analysed the protein content in the hair to gain insights into an individual’s genetic predispositions. Another area that gives hope is the use of AI and machine learning algorithms to analyse hair morphology. The algorithms can reveal important features through which identification will become easy.

Forensic trichology is still an essential part of contemporary criminal investigations. From its humble beginnings to the adoption of sophisticated technologies, it has proven its value time and again. The recognition of hair evidence by the Supreme Court of India and its application in high-profile cases underscores its reliability and importance. Forensic trichology is advancing with research and technology, enhancing precision in justice. Society's ability to uncover the truth evolves with science, ensuring a thorough examination of every strand of evidence.

(Dr. Kumar is a forensic consultant to the Assam government. Bora is a student of National Forensic University, Guwahati.)