Visualization of gunshot residue patterns on dark clothing

Area of Science:

• Forensic Science
• Ballistics
• Imaging Technology

Background:

• Determining muzzle-to-target distance is crucial in firearm investigations.
• Detecting gunshot residue (GSR) on dark or bloodstained clothing is challenging.
• Traditional methods like infrared film require development and may need multiple exposures.

Purpose of the Study:

• To evaluate the Video Spectral Comparator 2000 (VSC 2000) for instantaneous detection of GSR patterns.
• To determine if the VSC 2000 can reliably visualize GSR on dark and bloodstained clothing without specialized film.
• To assess the VSC 2000's effectiveness across various firearm calibers and muzzle-to-target distances.

Main Methods:

• Test fires were conducted using eight different handgun calibers at 6, 12, and 18 inches.
• Five types of dark clothing, some bloodstained, were used as targets.
• The VSC 2000 was employed with appropriate instrument settings to capture GSR patterns.

Main Results:

• GSR patterns were detected for all eight calibers tested.
• Powder burn patterns were visible on dark clothing at all tested distances for most calibers.
• Bloodstains did not prevent the viewing of GSR patterns using the VSC 2000.
• Exceptions were noted for 0.22 long rifle and 0.25 ACP calibers.

Conclusions:

• The VSC 2000 provides rapid, reliable, and instantaneous visualization of GSR patterns on challenging clothing substrates.
• This technology offers a significant advancement over traditional methods for forensic firearm analysis.
• The VSC 2000 aids in determining muzzle-to-target distance, even on dark or bloodstained evidence.