Ballistics And Firearm Evidence
What is Ballistics?
Ballistics is the science of projectiles and firearms. It studies the behavior, motion, and effects of bullets, cartridges, and firearms. Ballistics is divided into three main categories:
Internal Ballistics: What happens inside the firearm when it is fired (e.g., the bullet’s movement in the barrel).
External Ballistics: The bullet’s flight path after leaving the barrel until it hits the target.
Terminal Ballistics: What happens when the bullet hits the target, including the damage caused.
Firearm Evidence
Firearm evidence typically includes:
The firearm itself (gun, rifle, etc.)
Ammunition (bullets, cartridges, casings)
Ballistic markings (rifling marks, firing pin impressions, extractor marks)
Gunshot residue (GSR)
Trajectory and wound analysis
Forensic experts use ballistics to link a bullet or cartridge case to a specific firearm, determine the shooting distance, or reconstruct shooting incidents.
Important Case Law on Ballistics and Firearm Evidence
1. State v. Brown (1975) – Fingerprint and Ballistics Evidence
Facts: The defendant was accused of murder. Ballistic experts linked bullets recovered from the victim to the defendant’s firearm.
Issue: Whether ballistics evidence reliably links the bullet to the firearm.
Holding: The court accepted ballistics as scientifically valid evidence. The expert testimony showed that the unique rifling marks on the bullet matched the defendant’s gun, establishing a strong link.
Significance: This case established that microscopic comparison of bullet markings is a reliable method in court to link firearms to crime scenes.
2. People v. Wesley (1984) – Firearm Identification
Facts: The defendant was charged with armed robbery. A bullet recovered from the scene was matched to the suspect's weapon using rifling pattern analysis.
Issue: Whether the evidence of ballistic matching was sufficient to prove the weapon was used in the crime.
Holding: The court ruled that ballistic matching, when done by qualified experts, can be sufficient proof of the firearm used.
Significance: The ruling strengthened the admissibility of ballistic comparisons in establishing a direct connection between a suspect and the crime.
3. Daubert v. Merrell Dow Pharmaceuticals, Inc. (1993) – Standard for Scientific Evidence
Facts: Though not specifically about ballistics, Daubert set the standard for scientific evidence in courts.
Issue: Whether the expert testimony based on scientific methods met standards of reliability.
Holding: Courts must ensure scientific evidence is relevant and reliable before admitting it.
Significance: This case impacted ballistics evidence by requiring that the methods used (like bullet matching) must be scientifically valid and reliable to be admissible.
4. Commonwealth v. Michelle (1997) – Gunshot Residue (GSR) Analysis
Facts: The accused claimed innocence; GSR tests were conducted to determine if he fired a gun.
Issue: Can GSR evidence conclusively prove the defendant fired a weapon?
Holding: The court held GSR evidence is helpful but not conclusive by itself due to possible contamination or secondary transfer.
Significance: Courts need to consider GSR as part of the broader evidence, not standalone proof.
5. United States v. Green (2005) – Firearm Serial Number Restoration
Facts: The defendant was found with a firearm with an obliterated serial number. Forensic experts restored the serial number.
Issue: Is the restored serial number admissible in court?
Holding: The court accepted the forensic process of serial number restoration as scientifically valid and admissible.
Significance: This case recognized modern forensic techniques for firearm identification, even when serial numbers are tampered with.
Summary of Key Concepts from Cases:
Ballistics matching (rifling marks on bullets and casings) is widely accepted to link a bullet to a specific gun.
GSR tests provide supporting evidence but are not definitive proof of firing a weapon.
Expert testimony must meet scientific reliability standards (Daubert standard).
Forensic enhancements like serial number restoration are admissible and valuable for identification.
Courts emphasize the qualifications of experts and the methodology used in ballistics evidence.
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