In an unattended death, the deceased has been there for anywhere from a few days to several weeks and decomposition has started. Human decomposition is a natural process involving the breakdown of tissues by bacteria after death. Every living being will start the process of decomposition once death has occurred. According to Forensic Anthropology, human decomposition begins around four minutes after a person dies and follows four stages:

1. Autolysis

2. Bloat

3. Active decay

4. Skeletonization