Forensic Microbiological Analysis of Soil and the Physical Evidence Buried in Soil Obtained from Several Towns in Istanbul

Background The identification of bacterial species in the soil can be used for the differentiation of soil samples and physical evidence. This study aims to evaluate the importance of identifying microorganisms in the soil for forensic sciences. The study covered 20 regions identified and marked outside the settlement areas within the boundaries of Istanbul. Methodology Big and wide soil and forest areas were preferred. Four types of physical evidence samples were collected from the identified areas at the end of the first, second, and third months and then analyzed. The collected samples were physically embedded in the soil. In this study, 10 g of soil sample and four pieces of physical evidence (fabric, rubber, metal, and wood), sized 5 x 5 cm and buried 20-30 cm deep in the soil, contaminated with soil were collected for analysis and stored in sterile conditions. The microbiological identification analyses were conducted at the end of the predefined period and in the predefined order using first phenotypic (e.g., microscopic and macroscopic), followed by culture methods using advanced diagnostic analyses, such as API and matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Results In the soil samples and the physical evidence samples collected, 83% bacteria and 17% fungus were identified. A database was set up for the study findings. Conclusions The presence of microorganisms in the soil and physical evidence samples contaminated with soil, which is crucial in the evaluation of criminal cases, was determined using microbiological analysis.