Post-mortem interval (PMI) is the time that has elapsed since a person has died. If the time in question is not known, a number of medical/scientific techniques are used to determine it. This also can refer to the stage of decomposition of the body.
Types of change after death
Many types of changes to a body occur after death. Some of those that can be used to determine the post mortem interval are:
Traditional decomposition stages
A person who judges the time of death by the means of decomposition can refer to a simple five-stage process:
- Stage 1: Initial Decay - Bacteria located mainly in the lower intestine begin decomposition, giving a greenish color to the lower abdomen.:17
- Stage 2: Putrefaction - Bacteria grow throughout the body, releasing gases, which in turn bloat the body and cause unpleasant odor.
- Stage 3: Black Putrefaction - This stage brings further discoloration to the body. The gases from bacterial decay begin to escape, causing strong odor.
- Stage 4: Butyric Fermentation - The internal organs liquefy and the body begins to dry out.
- Stage 5: Mummification - This is the slowest of the five stages. In a hot, dry climate the body may dehydrate, inhibiting bacterial decay; the skin dries to a dark leathery appearance.:17
More advanced methods
More advanced methods include DNA quantification and infrared spectroscopy.
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Survey of Biological Factors Affecting the Determination of the Postmortem Interval. Bautista, Richard. Spring 2012.
- ↑ 2.0 2.1 Blood, guts, gore and soil: decomposition processes in graves and forensic taphonomic applications. Tibbett, Mark. 2010 19th World Congress of Soil Science, Soil Solutions for a Changing World.
- ↑ Muñoz, JI; Suárez-Peñaranda, JM; Otero, XL; Rodríguez-Calvo, MS; Costas, E; Miguéns, X; Concheiro, L (2001). "A new perspective in the estimation of postmortem interval (PMI) based on vitreous". Journal of forensic sciences 46 (2): 209–14. PMID 11305419.
- ↑ Lin, X; Yin, YS; Ji, Q (2011). "Progress on DNA quantification in estimation of postmortem interval". Fa yi xue za zhi 27 (1): 47–9, 53. PMID 21542228.
- ↑ Huang, P; Tuo, Y; Wang, ZY (2010). "Review on estimation of postmortem interval using FTIR spectroscopy". Fa yi xue za zhi 26 (3): 198–201. PMID 20707280.