There is sheer lack of awareness of a simple diatom test that can be of great help in forensic investigations, especially in cases of death due to drowning, said forensic pathologist Dr TD Dogra, while inaugurating a national workshop on the role of diatoms in forensics at MACS Agharkar Research Institute on Monday.
Diatoms are aquatic plants which play an important role in investigations, especially in cases of drowning. They help in locating the place of drowning, said Dogra, former director of AIIMS, New Delhi, citing instances where a simple diatom test had proved effective and the forensic team could establish in court that certain murder cases were actually deaths due to drowning.
Dogra gave the instance of the ‘rape and murder’ case of Neelofar Jan and her 17-year-old sister-in-law in Shopian. “We used the diatom test that attributed the death to accidental drowning,” he said.
Diatoms found inside the body of a drowned victim may serve as corroborative evidence in diagnosing the cause of death, Dr Karthick Balsubramanian, a scientist involved in research on diatoms at ARI, said. Diatoms are diverse microscopic algae with silica cell walls that are found in almost every aquatic environment including fresh and marine waters.
If the person is still alive when entering the water, diatoms will enter the lungs if the person inhales water and drowns. The diatoms are then carried to distant parts of the body such as brain, kidneys and bone marrow by circulation. If the person is dead when entering the water, then there is no circulation and the diatoms cannot enter the body.
Diatoms do not occur naturally in the body. If laboratory tests show diatoms in the corpse that are of the same species found in the water where the body was recovered, then it may be good evidence of drowning as the cause of death, the scientist explained.
Earlier Dr K M Paknikar, Director of ARI, said the institute is creating a database of diatoms in Maharashtra for preserving biodiversity.
While Dogra urged more awareness about the role of diatoms, the three-day workshop will train officers, academicians, research scholars and students in the field of forensic science on their role in crime investigations and overcoming shortcomings associated with diatom analysis.