[A retrospective analysis of estimating postmortem interval in 256 murder cases]

Area of Science:

• Forensic Science
• Criminalistics
• Thanatology

Background:

• Accurate postmortem interval (PMI) estimation is crucial in forensic investigations.
• Traditional methods for PMI determination can be subject to significant error, particularly in cases with decomposition or environmental challenges.

Purpose of the Study:

• To evaluate the accuracy of traditional postmortem interval estimation methods.
• To identify factors contributing to inaccuracies in PMI determination.
• To propose methods for reducing errors in PMI estimation.

Main Methods:

• Analysis of 256 solved homicide cases with known PMIs (January 2003 - January 2013).
• Comparison of traditionally estimated PMIs with actual PMIs.
• Grouping cases by PMI duration and calculating accuracy rates.
• Identification and analysis of common reasons for estimation errors.

Main Results:

• High accuracy for early PMIs (90% for <12h, 89% for 13-24h).
• Decreasing accuracy for later PMIs, ranging from 79% (1-7 days) down to 50% (1-5 years).
• Common error factors include improper inference, body submersion, extreme temperatures, lack of evidence, and scene alteration.

Conclusions:

• The accuracy of postmortem interval estimation declines significantly as time progresses.
• Factors such as environmental conditions and scene integrity critically impact estimation accuracy.
• Employing multiple data indices offers a promising approach to enhance the precision of postmortem interval estimations.