The circumstances of death and the estimation of the post-mortem interval (PMI) are often a great challenge for scientific and judicial investigators, especially when some time has elapsed since death. Several techniques are used; nevertheless, each presents its own limitations. In the quest for new techniques that are more reliable or at least complementary to those existing and sometimes less expensive, researchers have in recent years turned toward exploring the dynamics of the different microbial communities of a corpse according to their different stages of decomposition. This article summarizes the various works done in the field and shows the different sources of microorganisms in the different parts of the human corpse and their potential interest in the field of forensic medicine.