What a DNA blueprint can achieve in crimebusting, where India lags still
DNA fingerprinting was first developed in 1984 by Alec Jeffreys in the UK, after Jeffreys discovered that no two people could have the same DNA sequence. DNA fingerprinting was first developed in 1984 by Alec Jeffreys in the UK, after Jeffreys discovered that no two people could have the same DNA sequence.
In March 2011, Bollywood actor Shiney Ahuja was convicted and sentenced to seven years of rigorous imprisonment for raping his maid — even though the victim had told the court that she was never raped. But the Sewri fast-track court, which delivered the verdict, relied heavily on DNA evidence, in which semen samples from the vaginal swab of the victim matched with the samples obtained from the accused.
It was DNA evidence that established the identity of Thenmozhi Rajaratnam, also known as Dhanu, the suicide bomber who killed Rajiv Gandhi on May 21, 1991. And until the blueprint — another word for DNA — of some charred bones were discovered in a forest in Raigad, Maharashtra, in August 2015, and matched with the DNA of media entrepreneur Indrani Mukherjea, she had maintained that her daughter Sheena Bora was away in the USA.
From 1995’s Naina Sahni murder case to modern-day incidents of terrorism such as the 2013 Hyderabad blasts, DNA fingerprinting has not only come of age, but is also being increasingly used for crime investigations and prosecutions.
As the scientific community mourned the demise on December 10 of Dr Lalji Singh, celebrated as “the father of DNA fingerprinting in India”, the focus is back on the technology he was associated with, the science which claims to have close to 100% accuracy.
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DNA fingerprinting was first developed in 1984 by Alec Jeffreys in the UK, after Jeffreys discovered that no two people could have the same DNA sequence. Within three years of the discovery, the UK achieved the world’s first conviction based on DNA evidence in a case of rape and murder. Crucially, the evidence also saved the life of an innocent man who had earlier been charged with the crime.
Lynda Mann, a 15-year-old girl, had been found raped and murdered in Narbourough, England. This was followed by a similar rape and murder case three years later in the same area. The police arrested one Richard Buckland, who confessed to both crimes. However, with the advent of DNA fingerprinting, his samples were checked against those found on the dead bodies — they didn’t match. Buckland was cleared and another man, Colin Pitchfork, was then arrested and convicted of the murders.
By 1988, Lalji Singh, who had been in the UK from 1974 to 1987 on a Commonwealth Fellowship, developed DNA fingerprinting for crime investigations at the Centre for Cellular and Molecular Biology (CCMB) in Hyderabad, which he joined after returning to India. In 1989, DNA fingerprinting was first used in a case by the Kerala Police. By the early 1990s, the technology had begun to be used for establishing paternity, and to link criminals and identify victims in sensational crimes. From the 2000s onwards, the technology became a staple in rape cases where vaginal swab samples were matched with semen samples from suspects.
The uniqueness of DNA fingerprinting as a tool of investigation is not just limited to its accuracy but extends to the way it can sift through crime scene evidence. Advanced DNA fingerprinting can make separate prints of various individuals even from a sample mixture found at the crime scene — for example, in a gangrape case, DNA fingerprinting can identify each of the individuals involved in the act through one sample. In such cases, it becomes the clinching evidence against the accused, and also helps exonerate those whose samples do not match.
DNA can typically be extracted from blood and semen stains on clothes or on the body, from hair and teeth (with roots), and even from bones and flesh if they are not completely charred. Under the Indian criminal justice system, there are broad guidelines on how DNA samples are to be collected from a crime scene. It is vital to ensure that the DNA of the investigators does not get mixed with that of the victims or the suspects. Thus, picking up samples from a crime scene with sterile tools and storing samples in a proper manner are crucial for the evidence to stand a judicial test.
And this is where India’s police forces have a lot of catching up to do with counterparts overseas. While central agencies such as the Central Bureau of Investigation (CBI) and the National Investigation Agency (NIA) have found DNA fingerprinting to be very effective, thus ensuring that crime scenes are protected and samples collected by forensic teams, state police forces are yet to be trained in conducting such scientific investigations.
“The Aarushi Talwar murder case of 2008 is a prime example. Because the crime scene was not made out of bounds, both police and media trampled all over it. Now the case has no evidence to conclusively establish who killed the 14-year-old girl. Until state police are trained to isolate the crime scene, scientific investigation cannot take place,” a senior UP Police officer said.
Contrast the NIA’s investigation in 2013’s Bodh Gaya blasts, where a Buddhist robe was found abandoned at the crime scene. The agency got a forensic team to pick up strands of hair from the robe — these matched with strands from the suspected bomber, Haider Ali, when he was arrested the following year. This has now become the most crucial piece of evidence against him, the case having gone to trial recently.
The problem, however, is not limited to police. There is also a serious paucity of capacity for DNA fingerprinting in the country. While several states have their own forensic labs, DNA fingerprinting is available only at a few places — Maharashtra, West Bengal, Delhi, Hyderabad and Chandigarh. Advanced practices in the technology are limited to the Centre For DNA Fingerprinting and Diagnostics (CDFD) in Hyderabad. There are also several private labs that offer DNA testing, but all work under an unregulated environment, as a law to regulate such institutions has lain in a limbo since 2003.
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