The recovery of severely altered cadavers (i.e., extensively decomposed, mummified, charred or dismembered) can be a challenge for forensic pathologists due to the difficulties in identification, PMI estimation and manner and cause of death determination. In such cases, integrating routine approaches (autopsy, histology, toxicology) to more specific forensic branches can be fundamental to improving the investigative process. In this paper a systematic review using PubMed, Scopus and Web of Science databases has been performed. The aim was to evaluate the forensic approaches implemented in the management of severely altered bodies due to decomposition, mummification, skeletonization, charring or dismemberment (to which we refer to as “complex”), and the role of each approach in the solution of a case. Then, the literature revision results were used to propose a schematic flowchart summarizing the post mortem activities that can be performed in forensic practice, adaptable in relation to each case.