A general approach for postmortem interval based on uniformly distributed and interconnected qualitative indicators.

Area of Science:

• Forensic Entomology
• Forensic Science
• Thanatology

Background:

• Postmortem interval (PMI) estimation is crucial in forensic investigations.
• Current methods often rely on indicator persistence time, which is complex and influenced by numerous unknown factors.
• Qualitative indicators, such as insect life stages, are valuable but require robust estimation techniques.

Purpose of the Study:

• To develop a novel method for estimating PMI using qualitative markers without relying on indicator persistence time.
• To introduce the concept of pre-appearance interval (PAI) for marker estimation.
• To validate the new method using carrion insect developmental stages and experimental data.

Main Methods:

• Developed a PMI estimation approach based on the pre-appearance interval (PAI) of qualitative markers.
• Defined PMI by the PAI of a present marker (lower bound) and an absent marker (upper bound).
• Calibrated the method using sequential life stages of carrion insects and tested with pig cadaver experiments.

Main Results:

• The new method successfully estimates PMI by considering the presence and absence of sequential insect developmental stages.
• Estimation of the pre-appearance interval (PAI) for these stages proved reliable.
• The approach provides a practical and accessible means for determining PMI in forensic casework.

Conclusions:

• The developed method offers a reliable and accessible alternative for PMI estimation in forensic contexts.
• Utilizing pre-appearance intervals (PAI) of carrion insect stages bypasses the complexities of persistence time estimation.
• This approach enhances the accuracy and practicality of postmortem interval determination.