There are 4 stages of post mortem changes seen in the body after death: Pallor Mortis, Algor Mortis, Rigor Mortis, and Livor Mortis. Death is one of the most fundamental facts of life. After we die, there are 4 stages of changes that occur in the body. They are used, primarily, to determine the time of death or post mortem index (PMI) in forensic pathology