It’s all in the DNA

Forensic DNA evidence, often hailed as the gold standard for identifying individuals, plays a crucial role in crime investigations and legal proceedings. It is instrumental in connecting suspects to crime scenes, exonerating the wrongly convicted, and establishing or excluding paternity. The reliability of forensic DNA evidence surpasses many other types of crime scene evidence, thanks to its high discrimination power, stability, and sensitivity. DNA tests are considered nearly infallible due to precise accuracy.

The pioneering work of Sir Alec John Jeffreys, a British geneticist, led to the development of genetic fingerprinting and DNA profiling techniques. These advancements are now globally utilized in forensic science to aid police investigations, resolve paternity disputes, and address immigration issues.

In India, forensic DNA evidence was first recognised in the criminal justice system by the Madras High Court in 1985. The landmark case of Kunhiraman v. Manoj (1991), adjudicated by the Kerala High Court, marked a significant milestone. The court upheld the admissibility of DNA evidence under Section 45 of the Indian Evidence Act, which permits expert opinions in legal matters. This ruling established that DNA evidence, like the opinions of chemical analysts or fingerprint experts, could decisively determine paternity.

Several high-profile cases in India have since relied on DNA evidence for crucial breakthroughs:

Rajiv Gandhi Assassination Case (1991): DNA fingerprinting was used to identify both the victims and the attacker.

Naina Sahni Murder Case (1995): DNA evidence confirmed that the burnt remains were those of Naina Sahni, leading to the conviction of Sushil Sharma.

Beant Singh Assassination Case (1995): DNA fingerprinting revealed that one of the victims was Babbar Khalsa operative Dilawar Singh, confirming suspicions of a human bomb attack.

Priyadarshini Mattoo Case (1995): DNA evidence played a key role in the conviction of Santosh Kumar Singh, with the Delhi High Court sentencing him to death in 2006 based on DNA evidence found on the victim’s undergarments.

Shiney Ahuja Rape Case (2009): The actor was convicted after DNA samples from the victim matched his. Nirbhaya Gangrape Case (2012): DNA evidence, along with the victim’s dying declaration, led to the death sentences of all accused.

Hyderabad Blasts Case (2013): DNA samples from a house linked to the accused helped the National Investigation Agency secure convictions.

Mumbai Shakti Mill Gang Rape Case (2018): DNA evidence was crucial in identifying the victim through personal belongings, leading to the conviction of the accused. Interestingly, DNA profiling has even been utilized in anti-corruption cases. For instance, a bribe taker who swallowed tainted currency notes was forensically implicated when DNA profiling of saliva on the recovered notes confirmed his guilt.

In essence, DNA evidence serves as a biological GPS for the accused—a divinely notified Aadhaar card, ensuring justice is served. Just as in cricket where catches win matches, in crime, DNA matches win convictions.

(The writer is a retired IPS officer and a forensic expert. Views personal.)