The effect of human decomposition on bullet examination

Area of Science:

• Forensic Science
• Ballistics
• Taphonomy

Background:

• Firearm-related homicides often require forensic examination of recovered bullets.
• Decomposition can damage bullets, complicating ballistic analysis, especially when removal is delayed.
• No prior studies have investigated bullet decomposition in an Australian context.

Purpose of the Study:

• To investigate the effects of human decomposition on fired bullets in various tissue types and environmental conditions.
• To determine the optimal timeframe for bullet recovery from decomposed bodies for ballistic analysis.

Main Methods:

• Seven fired copper-jacketed bullets were inserted into lung, abdominal, and leg muscle tissues from human donors.
• Samples were maintained in cool and warm conditions at the Australian Facility for Taphonomic Experimental Research (AFTER).
• Bullets were retrieved every three days for 21 days and microscopically examined by firearms examiners.

Main Results:

• Bullets corroded more rapidly in warm decomposition conditions compared to cooler conditions.
• The extent of bullet damage was influenced by decomposition and environmental temperature.
• Microscopic examination revealed significant corrosion patterns over time.

Conclusions:

• Prompt removal and examination of fired bullets from decomposed bodies are crucial for effective ballistic investigation.
• Warm environmental conditions accelerate bullet corrosion, emphasizing the urgency of recovery.
• Findings will assist investigators and pathologists in optimizing evidence recovery from decomposed remains.