Microscopic algae can provide supporting evidence in forensic investigations involving aquatic environments. Diatoms are among the most widely studied groups in this field. These single-celled algae possess silica shells that favour preservation and allow microscopic identification in environmental and forensic samples. Diatom testing is used as a supplementary examination in suspected drowning cases. It involves examining body samples and comparing findings with water samples. One pilot study investigated sampling from sternal bone marrow, lungs, and other tissues in suspected drowning victims to assess collection methods and reduce contamination risks. Careful sample collection and laboratory processing are essential because contamination can produce misleading findings. Clean equipment, suitable laboratory controls, and documented procedures are therefore necessary. A recent study highlighted the importance of recognizing sources of diatom contamination during laboratory work. The presence of diatoms alone does not prove drowning, and their absence does not conclusively exclude it. Results must be interpreted alongside the circumstances of body recovery, autopsy findings, and other examinations. In conclusion, algal analysis demonstrates the value of integrating life sciences with forensic medicine. These microscopic organisms may provide supporting evidence that helps explain deaths associated with aquatic environments.