Kolkata godown blaze: forensic investigation stalled by wreckage, DNA tests to identify victims
Kolkata — A massive fire that gutted a warehousing complex in Kolkata has left forensic teams struggling to recover usable evidence amid collapsed structures and tangled debris, investigators say. With the death toll continuing to rise, authorities have planned DNA testing to identify badly charred and skeletal remains — a process that could take days to weeks depending on sample quality and laboratory workload.
Investigators at the scene describe an operation hampered by unstable structures, heat-damaged material, and extensive accumulation of ash and debris — all of which make the routine collection of biological evidence and trace materials extremely difficult. The circumstances have forced a shift from on-scene identification to comprehensive laboratory work, with DNA profiling now central to confirming the identities of the deceased.
Scene conditions complicate evidence recovery
Firefighters contained the blaze after several hours, but the structural collapse that followed has left large sections of the godown inaccessible and dangerous to enter. Forensic teams working with the police have focused on two immediate priorities: (1) ensuring the safety of recovery personnel and (2) stabilizing the scene so that evidence can be collected without further contamination.
Typical on-scene forensic actions — such as mapping, photographing, and methodical recovery of biological samples — are constrained by:
- Unstable roof and wall sections that require engineering checks before entry.
- Fragmentation and charring of remains, which reduce the volume and integrity of recoverable tissue.
- Heat-altered environmental indicators (e.g., melted plastics, ash clouds) that obscure trace evidence and can degrade DNA.
- Cross-contamination risks from rescue and firefighting activity that can deposit external biological material into the scene.
Because of these factors, investigators have concentrated on careful documentation and selective recovery of remains that are accessible and appear to retain biological material. Trained disaster victim identification (DVI) teams and forensic pathologists are coordinating to prioritize remains for laboratory testing.
DNA testing becomes the primary identification route
When visual identification or fingerprints are impossible due to the condition of the remains, DNA profiling becomes the gold standard. In this case, authorities have announced plans to submit recovered biological samples for DNA analysis to confirm identities and provide closure for grieving families.
DNA-based identification in fire victims typically follows several steps:
- Sample triage on scene: Forensic teams identify samples most likely to yield amplifiable DNA (teeth, femur bone, deep muscle).
- Chain of custody and contamination control: Samples are packaged, labeled, and transported under strict protocols to preserve evidentiary value.
- Laboratory extraction and quantification: Forensic labs extract DNA and assess quantity/quality; heavily degraded samples may require specialized extraction techniques.
- STR or mtDNA analysis: STR profiling is standard; mitochondrial DNA may be used when nuclear DNA is too degraded.
- Reference sample comparison: Profiles are compared with DNA from relatives, personal items, or databases.
- Statistical validation and reporting: Match probabilities are calculated and formal reports prepared.
Challenges and capacity issues
Experts note several challenges that can slow DNA identification in large fire incidents:
- Degraded DNA quality due to extreme heat exposure.
- High volume of commingled remains increasing analytical complexity.
- Delays in obtaining reference samples from families.
- Limited laboratory throughput and backlogs.
Given these constraints, forensic officials caution families and the public that identification and formal confirmation are likely to take days to weeks, not hours.
Human impact and next steps
Relatives of missing workers have gathered at temporary inquiry centers and hospitals, anxiously awaiting confirmation. Authorities have urged family members to provide reference samples (buccal swabs) and documents that can expedite the identification process.
Investigative next steps include:
- Continued careful recovery of remains as structural stabilization permits.
- Prioritization of samples for DNA testing based on likelihood of success.
- Coordination with regional forensic laboratories for rapid analysis.
- Preservation of the scene for parallel criminal or regulatory inquiries.
For the aspiring forensic professional
This incident highlights key realities of forensic practice in mass-casualty fire events, including the importance of scene safety, specialized DNA strategies, strict chain-of-custody protocols, and interagency coordination.
Closing
As forensic teams shift from hazardous field recovery to laboratory analysis, authorities say DNA testing will play a central role in identifying victims and advancing the investigation. Families and the community are being asked for patience while scientific and safety constraints are navigated.
