Post-mortem interval

Michele Taylor - Forensics Final Project (1)

The post-mortem interval (PMI) is the time that has elapsed since an individual's death. When the time of death is not known, the interval may be estimated, and so an estimated time of death established. There are standard medical and scientific techniques supporting such an estimation.

Examination of body scene of death and the body

Changes to a body occurring after death (post-mortem changes) include:

Conditions at the scene of death affect the estimation of time of death. To algor mortis, livor mortis and rigor mortis, together with consideration of stomach contents, there need to be some observation of environmental conditions at the death scene.[1] Body habitus and clothing also affect the rate of cooling of the body, and so its rate of decomposition.[2]

Analytical techniques

There are analytical techniques that can be used to determine the post-mortem interval:[3]

  • Forensic entomology: insect (especially blowfly)[3]: 2  activity on the corpse;
  • Vitreous humour changes: eye chemistry;[4][5]
  • State of decomposition: autolysis (process of self digestion) and putrefaction (process caused by bacteria found within the body).

More advanced methods include DNA quantification,[6] infrared spectroscopy,[7] and for buried individuals changes in soils such as the levels of methane,[8] phosphates and nitrates,[9] ninhydrin-reactive nitrogen,[10] volatile organic compounds,[11] and water conductivity.[12]

References

  1. ↑ Dix, Jay; Graham, Michael (7 December 1999). Time of Death, Decomposition and Identification: An Atlas. CRC Press. p. 1. ISBN 978-1-4200-4828-5.
  2. ↑ FBI Law Enforcement Bulletin. Federal Bureau of Investigation, U.S. Department of Justice. 1973. p. 12.
  3. 1 2 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.
  4. ↑ Zilg, B.; Bernard, S.; Alkass, K.; Berg, S.; Druid, H. (17 July 2015). "A New Model for the Estimation of Time of Death from Vitreous Potassium Levels Corrected for Age and Temperature". Forensic Science International. 254: 158–166. doi:10.1016/j.forsciint.2015.07.020. hdl:10616/44849. PMID 26232848.
  5. ↑ Kokavec, Jan; Min, San H.; Tan, Mei H.; Gilhotra, Jagjit S.; Newland, Henry S.; Durkin, Shane R.; Casson, Robert J. (19 March 2016). "Antemortem Vitreous Potassium May Strengthen Postmortem Interval Estimates". Forensic Science International. 263: e18. doi:10.1016/j.forsciint.2016.03.027. PMID 27080618.
  6. ↑ 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.
  7. ↑ 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.
  8. ↑ Davla, M; Moore, TR; Kalacska, M; LeBlanc, G; Costopoulos, A (2015). "Nitrous Oxide, Methane and Carbon Dioxide Dynamics from Experimental Pig Graves". Forensic Science International. 247: 41–47. doi:10.1016/j.forsciint.2014.12.002. PMID 25544693.
  9. ↑ Senos Matias, MJ (2004). "An Investigation into the Use of Geophysical Methods in the Study of Aquifer Contamination by Graveyards". Near Surface Geophysics. 2 (3): 131–136. doi:10.3997/1873-0604.2004010.
  10. ↑ Van Belle, LE; Carter, DO; Forbes, SL (2009). "Measurement of Ninhydrin Reactive Nitrogen Influx into Gravesoil during Aboveground and Belowground Carcass (Sus domesticus) Decomposition". Forensic Science International. 193 (1–3): 37–41. doi:10.1016/j.forsciint.2009.08.016. PMID 19773138.
  11. ↑ Vass, A (2012). "Odor Mortis". Forensic Science International. 222 (1–3): 234–241. doi:10.1016/j.forsciint.2012.06.006. PMID 22727573.
  12. ↑ Pringle, JK; Cassella, JP; Jervis, JR; Williams, A; Cross, P; Cassidy, NJ (2015). "Soilwater Conductivity Analysis to Date and Locate Clandestine Graves of Homicide Victims" (PDF). Journal of Forensic Sciences. 60 (4): 1052–1061. doi:10.1111/1556-4029.12802. PMID 26190264. S2CID 12082791.
This article is issued from Offline. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.