A 35-year-old male is found dead in his locked apartment in Delhi. The body is brought to the mortuary 48 hours after discovery. On external examination, the body shows greenish discoloration over the right lower abdomen with skin slippage in patches. The investigating officer needs to establish the approximate time since death. Which investigation is most appropriate to confirm the stage of putrefaction and estimate the postmortem interval?

Explanation

## Investigation of Choice for Postmortem Interval Estimation ### Clinical Context The external findings of greenish discoloration and skin slippage indicate the body is in the early putrefactive stage (24–72 hours postmortem). The question asks for the MOST APPROPRIATE investigation to confirm this stage and estimate the postmortem interval. ### Why Entomological Examination is Correct **Key Point:** Entomological examination (study of insect colonization, particularly fly larvae/maggots) is the gold standard for estimating postmortem interval in the putrefactive stage, especially when the interval is between 24 hours and several weeks. **High-Yield:** Insects colonize a body in a predictable sequence: - **Blowflies (Calliphoridae)** arrive first (within 24–48 hours in warm climates like Delhi) - **Maggots** develop through three larval stages with characteristic timelines - **Beetle larvae** and other insects follow in later stages **Clinical Pearl:** The developmental stage of maggots (egg → 1st instar → 2nd instar → 3rd instar → pupation) can be correlated with ambient temperature to calculate the postmortem interval with ±1–2 days accuracy. ### Why Other Options Are Incorrect | Investigation | Limitation | |---|---| | **Histopathology (liver/kidney)** | Autolytic changes are non-specific and occur over weeks; cannot distinguish between 24–72 hours with precision | | **Bacterial culture & toxicology** | Useful for cause of death, not for timing; bacterial overgrowth is unpredictable | | **Radioisotope dating** | Used for skeletal remains (years to centuries old); inappropriate for recent deaths | **Mnemonic:** **FLIES** = **F**irst insects, **L**arvae development, **I**nterval estimation, **E**ntomology, **S**pecific timing ### Diagram: Insect Colonization Timeline ```mermaid flowchart TD A[Body in Putrefactive Stage<br/>24-72 hours]:::outcome --> B{Entomological Examination}:::decision B -->|Identify insect species| C[Blowfly/Calliphoridae present?]:::action C -->|Yes| D[Assess larval stage]:::action D --> E[1st/2nd/3rd instar larvae?]:::action E -->|Correlate with ambient temp| F[Calculate PMI<br/>±1-2 days accuracy]:::outcome B -->|Alternative: Histology| G[Non-specific autolysis<br/>Low precision]:::urgent ``` **Citation:** Parikh CK, Textbook of Forensic Medicine & Toxicology, 7e, Ch 3 (Thanatology & Postmortem Changes)