Background and aims: The diagnosis of drowning is a major challenge in forensic practice, particularly when bodies are recovered from aquatic environments in an advanced state of decomposition. Under such circumstances, classical autopsy findings are often obscured, necessitating the use of ancillary techniques. Diatom analysis has emerged as a valuable forensic tool for supporting the diagnosis of antemortem drowning and assisting in the identification of the probable site of drowning. The aim of this case series is to evaluate the forensic utility of diatom analysis in establishing the cause of death and correlating the probable site of drowning in decomposed bodies recovered from freshwater environments. Methods: A case series of six freshwater drowning cases was examined at the Central Forensic Science Laboratory, Chandigarh, India. Bone samples (sternum and femur) and corresponding reference water samples were subjected to acid digestion using concentrated nitric acid. Extracted samples were centrifuged, washed, and mounted on microscopic slides. Diatoms were identified using light microscopy at 100× magnification and compared morphologically between tissue and reference water samples. Results: Diatoms were detected in tissue and corresponding water samples in four cases, showing morphological similarity and taxonomic concordance. In two cases, diatoms were absent in bone samples but present in reference water samples, suggesting causes of death apart from drowning. The findings supported antemortem drowning in four cases and excluded drowning in two cases. Conclusion: Diatom analysis was a reliable adjunct in the forensic diagnosis of drowning, particularly in decomposed bodies. The presence of diatoms in bone samples strongly supported antemortem drowning, while negative tissue findings aided in excluding drowning. The correlation of diatom profiles between tissues and water sources strengthened medico-legal conclusions regarding both the cause and the site of death.
Keywords: Ante-mortem drowning; post-mortem drowning; sternum; asphyxia; acid digestion.