Algal communities differ between aquatic environments. Their examination may therefore help compare forensic samples with potential environmental sources. This approach considers the combination and relative abundance of organisms rather than relying on a single species. One applied study used quantitative diatom analysis to compare lung and clothing samples with local and regional reference samples. In one case, the findings showed statistically significant similarities to samples from shallow-water habitats, demonstrating how environmental comparisons may support event reconstruction. Alongside microscopy, molecular techniques allow researchers to examine diatom genetic material in water. A study involving 166 samples from 64 locations assessed whether this approach could identify water sources. Distinguishing freshwater from seawater proved easier than identifying precise geographic locations. These results show that molecular analysis is a promising comparative tool, but it does not establish a confirmed geographic location for every sample. Interpretation requires suitable reference samples, reliable environmental information, and consideration of similarities between different locations. In conclusion, combining algal science with molecular techniques can strengthen the study of environmental evidence. It may help guide investigations and assess possible sample sources within the limits supported by scientific findings