Effects of human decomposition on bullet striations

Area of Science:

• Forensic Science
• Materials Science
• Decomposition Studies

Background:

• Rifling striations on bullets are critical for forensic identification.
• Bullet material and its interaction with biological tissues during decomposition are not fully understood.
• Understanding post-mortem bullet degradation is essential for accurate forensic investigations.

Purpose of the Study:

• To investigate the effects of different bullet materials and body regions on bullet corrosion.
• To determine how decomposition influences the preservation of rifling striations.
• To assess the significance of material reactivity and anatomical location in post-mortem bullet alteration.

Main Methods:

• Five distinct bullet types (representing common centerfire handgun and rifle ammunition materials) were inserted into a fresh cadaver.
• Bullets were placed in cranial, chest, abdominal cavities, muscle, and adipose tissues.
• Bullet retrieval occurred after 90% decomposition, with photographic analysis comparing pre- and post-mortem states.

Main Results:

• Bullet material reactivity and the specific body region significantly influenced the corrosion process.
• Corrosion patterns varied based on the bullet's composition and its location within the decomposing cadaver.
• The observed corrosion potentially obscured critical rifling striations, impacting identification.

Conclusions:

• Bullet material and anatomical location are key factors in post-mortem bullet corrosion.
• Decomposition can significantly alter bullet surfaces, potentially hindering forensic analysis of rifling marks.
• Further research is needed to fully characterize bullet-tissue interactions during decomposition for improved forensic outcomes.