The characterization, analysis and validation of evidence that concludes the description of an intentional act of biocrime or bioterrorism represent the main target of microbial forensics. But, even nowadays with the most recent technical advances, it remains extremely difficult, labour-demanding and time consuming to investigate and confirm the origin of microbial strains and to identify the person or motif behind the crimes. The true extent of microbial diversity in indoor or outdoor environments may still be underestimated, but its origin and maintenance is starting now to be better understood. Biogeographic patterns and proves of endemism had been occasionally described for few bacterial communities, as well as for fungal populations. Other researchers sustain that microbes are simply so abundant that dispersion and migration capacities support a probable global distribution. Additionally, they possess a remarkable tolerance and adaptation abilities to the most unfavourable environmental conditions. Human body represents other sort of microbial community different from soil and water communities that may be ruled by other variables, particularly the individual genetic background. Nowadays, there is no doubt that molecular markers are important for microbe discriminating and, thus, genotyping methodologies are increasing interest for forensic sciences. The advent of large-scale genotyping studies on microbial populations may provide a unique opportunity to compare genetic diversity within and among populations. The present mini-review focus the most recent developments regarding microbial genetics and population diversity, both community richness and genotype diversity, and its application for criminal cases and forensic evidence.