Interpol guidelines to DNA matching: The painstaking work to find Ahmedabad plane crash victims' families some closure

Indian Express

21-06-2025

A crowd near the entrance of the 1,200-bed Ahmedabad Civil Hospital on June 15 piqued Rohit Patel's curiosity. Moments later, Rohit, a grizzled man in a cerulean shirt who had been perched outside the mortuary complex since June 12, followed the crowd, squeezing into a gap behind a table. At this table, three Gujarat officials were giving updates on the identification status of the June 12 air crash victims.
Minutes after take-off from Ahmedabad's Sardar Vallabhai Patel International Airport, a London-bound Air India flight with 242 people went down, its tail striking the first-floor mess at B J Medical College and Hospital, located a kilometre away, killing 241 onboard and at least 19 people on the ground.
Interrupting the officials, Rohit, who had travelled to Ahmedabad from Kheda district, around 50 km away, said, 'My nephew and his wife were on the plane. I have been at the hospital since the crash. We submitted a DNA sample on June 12. We were told their bodies would be given to us today (June 15) but now officials are saying they need more time to identify the remains.'
Turning around, Dr Rajnish Patel, Additional Medical Superintendent, Ahmedabad Civil Hospital, replied, 'We (doctors and the Forensic Science Laboratory) are working as fast as possible but checking each sample carefully takes three-four days. Please come here only after you get a call from us. We will handhold you through the entire process.'
With most victims charred beyond recognition, including 12 people at the crash site, confirming their identities correctly has been a formidable task. As of 11.50 am on June 20, 223 victims had been identified and 204 remains handed over to families. Officials say the final toll will be declared after the DNA profiling of all victims is complete.
Even as families described the wait for the bodies as 'painful', an official at Ahmedabad Civil Hospital says, 'We are following the Disaster Victim Identification (DVI) guidelines prescribed by Interpol (largest international police organisation with 196 member nations). Bodies are also being embalmed and put in sealed coffins before being handed over to kin.'
The three primary identifiers, according to the 2023 DVI guidelines, are 'fingerprints, odontology (dental examination) and DNA profiling'. Secondary identifiers include 'tattoos, scars and ornaments', but are considered 'inaccurate'.
Dr Jayasankar P Pillai, a forensic odontologist at Ahmedabad's Government Dental College, stepped in to help extract dental DNA and compile a dental charting of the victims. A different team profiled DNA samples later.
Given the magnitude of the tragedy, Dr Pillai says he knew he needed help with the work. 'I sent a message seeking help from my current and former students. Fifty of them turned up at the hospital within hours. We began autopsies, dental examinations and DNA sample collections around 6 pm on June 12. By 4.30 am on June 13, the process was completed for most victims.'
The autopsy required doctors from the Departments of Forensic Odontology and Forensic Medicine to collect samples of each victim's teeth and bones, which were sent to the Forensic Science Laboratory (FSL). At FSL, these samples were matched against those obtained from their relatives — the second step of identity confirmation and the gold standard. The third step — fingerprint analysis — could not be conducted since most bodies were charred in the fire that broke out after the crash.
Explaining why molars were 'the best bet' to find a DNA sample in this case, Dr Pillai says, 'Teeth can usually withstand higher temperatures than our bodies. The rotation and gaps between teeth are unique to each person, like fingerprints. The melting point of a metal or ceramic crown (from a root canal treatment) is higher. Even if a tooth is destroyed, it is unlikely that the crown would be destroyed too.'
In case his team found a dental crown, he says they asked the kin for the victim's dental records. 'This ante- and post-mortem comparison of dental characteristics, coupled with DNA profiling, leaves nothing to chance.'
Dr Tamanna Parmar, a periodontologist, was at her clinic, nearly 15 km from the Civil Hospital, when she heard about the crash. Having completed her post-graduation from the Government Dental College in 2024, she called up her juniors in college immediately. 'They told me they had left the mess just 15 minutes before the crash.'
Then, she says, she received Dr Pillai's message seeking help. Two hours later, she and two of her batch-mates were at the hospital. 'Due to barricading near the hospital, we had to park our vehicles 1 km away and walk,' she says.
The mortuary complex, she says, is a sight that she will 'never forget' — the fire and rigor mortis (stiffening of the body after death) had caused many bodies to twist badly. 'It took two people to just straighten them before we could start the dental exam. I looked for dental characteristics specific to victims and made observations on dental treatments or prosthetics in their mouths,' Dr Parmar says.
The DNA samples — teeth and bones — were put inside labelled containers and transferred to the FSL.
DNA profiling and matching took place at two laboratories — the Directorate of Forensic Science (DFS) and the Centre of Excellence in DNA Analysis at the National Forensic Sciences University (NFSU) — both located on the same road in Gandhinagar, around 20 km from the Civil Hospital.
At NFSU, the opening of all samples was videographed for evidence, Professor (Dr) S O Junare, director, Gujarat campus, NFSU, tells The Indian Express. 'The samples were cleaned thoroughly with distilled water and chemicals to remove all traces of someone else's DNA,' he says, adding that this step was necessary because multiple persons had come in contact with the bodies — from rescue to medical personnel.
Stating that extracting DNA from blood is easier, an NFSU forensic expert says, 'We powder the teeth or bones and then use the magnetic bead-based extraction method to get the DNA. This can take nearly 10 hours. To check if that sample is viable, it is run through another test (q-PCR) before profiling starts.'
At this point, Dr Junare says, the team is able to ascertain the victim's gender. Diluted and using a 24-marker kit (24 genetic markers), the DNA is run through a genetic analyser to create a genetic profile. 'The entire process takes 72-96 hours,' a scientist says.
Reference blood samples from living relatives — collected at B J Medical College's Kasauti Bhavan at the time of autopsies — went through the same process before the comparative analysis. 'Reference samples are matched against all deceased samples till we get a hit,' says Dr Junare.
A major challenge in such tragedies, he says, is the death of an entire family. 'In these cases, we take reference blood samples from grandparents or uncles or nieces,' he says.
Since DNA is measured in centimorgans (cM) to determine the closeness of the relation, the higher the cM value, the closer the degree of relation. For instance, we share around 25% of our DNA with each grandparent, say experts. In these cases, the Y chromosome short tandem repeat (Y-STR) markers and X-STR markers are used to determine paternal and maternal lineage respectively, he says.
Another obstacle is determining the correct identity of siblings or identical twins belonging to the same gender. While siblings share almost 50% of their DNA, most identical twins have almost completely identical DNA.
While their DNA profiling was on, the bodies of most victims were embalmed. Dr Dharmesh Patel, Head, Department of Forensic Medicine, Civil Hospital, said in a statement, 'The bodies were embalmed so that they could sustain long-distance travel.'
Though most final rites took place across Gujarat, in some cases, the bodies were sent to Nagaland and even the United Kingdom. Explaining the process, Dr Patel says, 'A chemical solution (like formaldehyde) is introduced into the body to preserve it. As per legal requirements, embalming and coffin sealing certificates were issued. Each victim's belongings were also duly certified.'
Dr Rakesh Joshi, Medical Superintendent, Civil Hospital, says the handing over of bodies to the families was the 'most critical part' of this process. 'Unfortunately, the body identification process is painstakingly slow, not only due to the implications it has for the family, but also the law.'
Gujarat Relief Commissioner Alok Pandey had recently said that the Treasury Department was working on getting inquest reports and insurance claims ready for families 'as soon as possible'. A 24/7 help desk has also been set up by the Gujarat State Legal Services Authority (GSLSA) to help families.
The most difficult identification so far has been that of minors. As per the airline manifest, 13 children aged 12 years and below were on the plane. While three had not yet turned 2 years old, the others were mostly aged between 11 and 18 years.
Officials say they were able to obtain just 'partial' DNA profiles for some 'whom we suspect are minors', making an 'accurate' match difficult.
Though DNA can be taken from any tooth in the case of children, accidents involving a fire complicate matters, says Dr Pillai. He explains, 'Heat degrades their front teeth. Also, children aged six years and below only have milk teeth. In such cases, we try to extract the permanent molars developing inside their jaws.'
The age of minors on the manifest also helped. 'Some of these minors had developed their second molars. So we knew they were between three to six years old. That helped narrow down their identification,' he adds.
(With inputs from Aditi Raja)