Stages of Decomposition: Forensic’s Blog

Autolysis Process

• The initial post-death process is the breakdown of cells by special enzymes (autolysis).
• Degraded cells become a food source for bacteria.
• Bacteria release putrefactive gases as they consume tissues.

Fresh Stage

• This stage occurs from death until the first signs of body swelling.
• Greyish skin, cell degradation, muscle relaxation, bladder, and intestines emptying.
• Insects are attracted within the first ten minutes after death.

Bloated Stage

• Gases from anaerobic bacteria cause abdominal swelling with putrefactive spots spreading.
• Changes: Tongue protrusion, fluid oozing from mouth/nose, putrefactive gas formation.
• Arthropod activities contribute to putrefaction and gas formation.

Decomposed Stage

• Skin detachment, liquid putrefactive formation (e.g., butyric acid), and decreased carcass weight.
• Changes: biomass conversion to dipteran larvae, Clostridium welchii as the principal putrefaction agent.

Decomposition Factors

• Description: Predictable colonisation sequence depends on the season, location, and intrinsic/extrinsic body factors.
• Variances: bodies clothed or undressed, buried, burned, or in water impact decomposition.

Advanced Decomposition Stage

• Presence of skin, cartilage, and tissue shreds attached to bone.
• Factors: Obese individuals putrefy more rapidly due to increased fluid.

Dry Stage

• Soft tissues and skin are absent, leaving only bones, tendons, hair, and nails.
• Bones can decay through diagenesis.

Insect Colonization

• Different stages of decomposition attract various insect species based on the degradation level.
• Factors: Season, geographic area, corpse location, and intrinsic/extrinsic body conditions affect colonization.
• Ecological Categories: necrophagous, saprophagous, predatory and parasitic, omnivorous, accidental.

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Multiple Choice Questions Stages of Decomposition

1: What is the primary role of autolysis in the decomposition process?

1. Release of gases
2. Breakdown of tissues
3. Attraction of insects
4. Formation of enzymes

2: What is the first sign of the Fresh stage?

1. Body swelling
2. Grayish skin
3. Cell degradation
4. Muscle relaxation

3: What causes the typical putrefactive spot during the Bloated stage?

1. Fluid oozing
2. Anaerobic bacteria
3. Arthropod activities
4. Abdominal swelling

4: What bacterium is the primary agent causing putrefaction in the Decomposed stage?

1. E. coli
2. Clostridium welchii
3. Staphylococcus aureus
4. Bacillus subtilis

5: Why do bodies of obese individuals putrefy more rapidly in this stage?

1. Increased bacterial activity
2. Greater fluid in tissues
3. Presence of cartilage
4. Higher ambient temperature

6: What is the main characteristic of the Dry stage?

1. Presence of skin
2. Absence of bones
3. Decay through diagenesis
4. Oozing of fluids

7: What factors influence the predictable sequence of insect colonization?

1. Geographic area only
2. Intrinsic body conditions only
3. Season, location, and extrinsic body conditions
4. Location and intrinsic body conditions

8: What is the role of putrefactive gases in the decomposition of a body?

1. Attracting insects
2. Breaking down cells
3. Contributing to tissue decay
4. Preventing autolysis

9: Which category of insects primarily feeds on dead tissue?

1. Necrophagous
2. Predatory
3. Parasitic
4. Omnivorous

10: What can affect the predictability of insect colonization in the decomposition process?

1. Intrinsic body conditions
2. Geographic area
3. Bodies being buried or burned
4. Season and location only

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Answer

1: B) Breakdown of tissues

2: B) Grayish skin

3: C) Arthropod activities

4: B) Clostridium welchii

5: B) Greater fluid in tissues

6: C) Decay through diagenesis

7: C) Season, location, and extrinsic body conditions

8: C) Contributing to tissue decay

9: A) Necrophagous

10: C) Bodies being buried or burned

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References

• Amendt J., Richards C. S., Campobasso C. P., Zehner R., Hall M. J. R., 2011. Forensic entomology: applications and limitations. Forensic Sci Med Pathol, 7:379-392.
• Bonacci T., Mendicino F., Bonelli D., Carlomagno F., Curia G., Scapoli C. Pezzi M., 2021. Investigation on Arthropods Associated with decay Stages of Buried Animals in Italy. Insects 2021, volume 12, Issue 4, 311.
• Bonacci T., 2018. Entomologia forense: insetti e indagini tecniche.  In Scienze Forensi, Anno 2, N.4.
• Byrd J. H., Castner J. L., 2010. Forensic entomology. The utility of arthropods in legal investigation. Second Edition. CRC Press, Danvers, USA. pp. 681.
• Campobasso C.P., Introna F., 2001. The forensic entomologist in the context of the forensic pathologist’s role. Forensic Sci Int 120:132–139.
• Catts E.P., 1992. Problems in estimating the post-mortem interval in death investigations. J Agric Entomol. 9:245–55.
• Elliott S., Lowe P., Symonds A., 2004. The possible influence of micro-organisms and putrefaction in the production of GHB in post-mortem biological fluid. Forensic Sci Int. 2004 Jan 28;139(2-3):183-90.
• Joseph I., Mathew D. G., Sathyan P., Vargheese G., 2011. The use of insects in forensic investigations: An overview on the scope offorensic entomology. J Forensic Dent Sci. 3(2): 89–91.
• LeBlanc H.N., Logan J.G., 2010. Exploiting Insect Olfaction in Forensic Entomology. Netherlands: Springer.
• Lord W. D., Stevenson J. R., 1986. Directory of forensic entomologist. 2nd ed. Washington, DC: Defense Pest Management Information Analysis Center, Walter Reed Army Medical Center.
• Stages of body Decomposition (https://forensicarticles.com/stages-of-body-decomposition/)
• Postmortem Lividity Discoloration (https://forensicarticles.com/postmortem-lividity-discoloration/)