Microbial decomposition in experimental single and mass graves: New insights on post-burial interval estimation

Area of Science:

• Forensic Science
• Microbiology
• Ecology

Background:

• Soil microbiomes are crucial forensic indicators.
• Microbial dynamics in mass graves are not well understood.
• Accurate post-burial interval estimation is vital in forensic investigations.

Purpose of the Study:

• To investigate microbial succession differences between individual graves (IG) and mass graves (MG).
• To evaluate soil microbiome data for predicting post-burial interval (PBI).
• To assess the generalizability of PBI prediction models across grave types.

Main Methods:

• Analysis of soil samples from controlled decomposition experiments in IG and MG.
• Utilized Amplicon Sequence Variant (ASV)-level assessment of microbial communities.
• Developed and tested regression models for PBI prediction.

Main Results:

• Significant differences in soil microbial composition were observed between MG and IG at 18 months post-burial.
• Specific microbial taxa were enriched in each grave type, correlating with decomposition stages.
• A PBI model trained on IG data performed poorly on MG samples, indicating context-specific variations.

Conclusions:

• Mass grave soil microbiomes exhibit unique dynamics compared to individual graves.
• Existing PBI prediction models developed for individual graves lack generalizability to mass graves.
• Further research into context-specific microbiome models is essential for accurate forensic reconstruction in mass grave scenarios.