Microbes: the invisible codes of forensic science

Microbial communities have recently emerged as promising biomarkers for forensic applications, offering novel perspectives to complement traditional approaches. This review aims to synthesise current evidence on how microbiome signals can be translated into usable forensic intelligence across crime-scene investigation and medico-legal casework.

This review summarizes advances in three key areas: soil evidence tracing, postmortem interval (PMI) estimation, and individual identification in sexual assault cases. Soil microbiome, shaped by geography and environment, provides distinctive signatures that can link evidence to specific locations. Dynamic microbial succession during decomposition provides a temporal indicator for PMI estimation, while human microbiota, with their site-specific and relatively stable features, show potential for identifying individuals and inferring physical contact. Alongside these applications, this review also briefly discusses past and current microbiome analysis techniques, as well as machine learning models.

Despite rapid advances, major obstacles remain, including instability of microbial communities and risks of contamination. Addressing these challenges will require validated protocols and robust to support reliable interpretation in forensic practice.