Forensics as a field comprises different disciplines, but not all of them meet the requisite thresholds of accuracy and precision to qualify as a “science”. Empirical studies have shown that the long-standing pattern of matching forensic evidence like fingerprints, ballistics, and bite mark evidence are incapable of unique identification, and are highly prone to error and bias. In contrast, forensic applications of scientific disciplines like DNA profiling, toxicology, chemical analysis and digital forensics which are backed by rigorous research, do not present similar concerns with their foundational validity.
DNA profiling offers unparalleled individualisation and incorporates checks for greater objectivity and verification of results. However, it has inherent limitations and is susceptible to error. DNA profiling cannot determine how and when the DNA was deposited. DNA is highly susceptible to contamination and may be deposited on an item either through direct contact or indirect transfer. DNA mixtures (i.e. samples with DNA from more than one individual), common in criminal cases, are more difficult to analyse than single-source DNA profiles. Various factors affect the complexity of DNA mixtures, and the more complex a DNA mixture, the greater the uncertainty surrounding its interpretation. Errors can occur at all stages of DNA profiling, therefore rigorous compliance with validated protocols is essential.
Anokhilal’s case underscores the problems with blind acceptance of DNA evidence. It was not until the third trial that the DNA expert was examined as a witness after obtaining the underlying laboratory documentation. It took repeated attempts to ensure proper appreciation of a main piece of evidence — a basic tenet in any criminal trial. While the science behind DNA profiling is foundationally valid, it does not mean that its practice in every case, by every “expert”, in every laboratory will be correct.
In this case, the DNA report concluded that the unknown hair strands found in the deceased’s fist, the DNA on her fingernails, and the DNA from one of the unknown stains on her pyjama, belonged to Anokhilal. The report also concluded that the deceased’s DNA was present in the DNA mixture on Anokhilal’s underwear. Based on these findings of the DNA report along with the circumstantial evidence that the deceased was last seen alive in Anokhi’s company before her body was found 36 hours later, the court concluded he was guilty.After a detailed cross-examination of the DNA expert in the third trial, it emerged that, firstly, the male DNA found in the vaginal and anal samples excluded Anokhilal as the source of the DNA. Secondly, there were discrepancies between the composition of the DNA detected in the samples and what was stated in the DNA report. Thirdly, the court recognised the possibility of tampering due to serious gaps in the collection and storage of samples in police custody and while they were at the lab. The chain of custody concerns with the unknown hair strands seized from the fist of the deceased were most significant. The prosecution claimed that these hair strands belonged to Anokhilal but the sample was never sealed or deposited in the police malkhana(evidence room) and the quantity and description of the hair strands received for DNA examination were different from the one that was seized initially.This case presents an important lesson for our criminal justice system — forensic science is a realm where the line between truth and error can be perilously thin. If the gold standard of forensic science, DNA profiling, is prone to faulty application, then other disciplines which lack foundational validity, warrant far greater scrutiny. Anokhilal’s ordeal should serve as an impetus for more accountability and rigorous monitoring of our forensic practice — a burden that must be borne by laboratory regulators, forensic practitioners, and legal actors alike.
This article first appeared on Hindustan Times and can be accessed here.
Shreya Rastogi is director, Death Penalty Litigation and Forensics at Project 39A. She argued Anokhilal’s case before the Khandwa Sessions Court during the third trial.