Full Answer Section

• • Serial Number: The serial number, if present and not obliterated, is a unique identifier for the firearm and can be traced back to the original purchaser.  
• Ballistics:
  • Bullet: The bullet recovered from the crime scene can be examined for rifling marks, which are unique impressions left by the gun’s barrel. These marks can be compared to test-fired bullets from the suspected firearm to determine if they match.  
  • Cartridge Case: The cartridge case ejected from the firearm after firing can also contain valuable information. It may have firing pin impressions, breech face marks, and ejector marks, all of which can be compared to those on cartridge cases test-fired from the suspected firearm.  
• Fingerprints:
  • Latent Fingerprints: Latent fingerprints may be present on the firearm’s surface, particularly on the grip, trigger, and magazine. These fingerprints can be compared to known fingerprints in databases to identify potential suspects.  
• DNA:
  • Touch DNA: Touch DNA can be collected from the firearm’s surface, which may contain traces of the person who handled it. This DNA can be compared to DNA profiles in databases to identify potential suspects.  
• Gunshot Residue (GSR):
  • GSR Particles: GSR particles can be found on the hands and clothing of the person who fired the gun. These particles can be collected and analyzed to determine if someone has recently fired a firearm.  
• Trace Evidence:
  • Fibers, Hair, etc.: The firearm may contain trace evidence such as fibers, hair, or other materials from the crime scene or the victim. This evidence can be used to link the firearm to the crime scene or the victim.  

2. Why the Casing Match Test is One of the Last for Firearms Examiners

Matching casings fired from 10 consecutively manufactured guns back to the weapon is a complex and meticulous process. It’s likely one of the last tests for several reasons:

• Time-Consuming: This type of analysis requires significant time and expertise to ensure accuracy. Examiners need to carefully examine and compare markings on each casing and bullet under a microscope, which can be very time-consuming.
• Resource Intensive: The process requires specialized equipment and resources, including a comparison microscope and a database of firearm markings.
• Complexity: Matching casings from consecutively manufactured guns can be particularly challenging because the markings may be very similar due to the manufacturing process. Examiners need to be highly skilled and experienced to differentiate between subtle variations.
• Importance of Accuracy: Firearms examiners play a critical role in the justice system, and their findings can have significant consequences. It’s crucial to ensure the accuracy of their analysis, and this requires thoroughness and attention to detail.

3. The Point of Using Consecutively Manufactured Weapons

The purpose of using consecutively manufactured weapons in this test is to assess the examiner’s ability to differentiate between subtle variations in markings on casings fired from very similar firearms. This is important because:

• Real-World Scenarios: In real-world crime situations, firearms used in crimes may be very similar or even the same make and model. Examiners need to be able to distinguish between them based on the unique markings on the casings and bullets.
• Quality Control: This test serves as a quality control measure to ensure that examiners are proficient in their analysis and can accurately match casings to the correct firearm, even when the differences are subtle.
• Scientific Rigor: This rigorous testing helps maintain the scientific integrity of firearms examination and ensures that the results are reliable and admissible in court.

4. History of the NIBIN/IBIS Program

• Early Development: The concept of using computer technology to compare firearm markings emerged in the late 1980s and early 1990s.
• Integrated Ballistic Identification System (IBIS): In the early 1990s, the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) developed the Integrated Ballistic Identification System (IBIS) to automate the process of comparing firearm markings.  
• National Integrated Ballistic Information Network (NIBIN): In 1999, the ATF and the FBI combined their ballistic imaging databases to create the National Integrated Ballistic Information Network (NIBIN).  
• NIBIN’s Growth: NIBIN has grown significantly since its inception and now includes images of firearm markings from crime scenes and test-fired weapons from across the United States.  
• Impact on Investigations: NIBIN has become an invaluable tool for law enforcement, helping to link crimes, identify suspects, and solve cold cases.  

5. NIBIN’s Role in the Murder of Gianni Versace

While NIBIN was not directly used to identify the firearm used in the murder of Gianni Versace, the case highlights the importance of firearm identification in criminal investigations.

• The Crime: Gianni Versace was murdered in 1997 outside his mansion in Miami Beach, Florida.  
• The Firearm: The murder weapon was a .40 caliber Taurus PT92 pistol.
• The Investigation: Investigators were able to trace the firearm back to its original purchaser, which helped them identify the suspect, Andrew Cunanan.
• NIBIN’s Potential Role: If the firearm had been previously used in other crimes and the markings had been entered into NIBIN, it could have potentially helped investigators identify Cunanan earlier.

The Versace case underscores the importance of firearm identification and the potential of programs like NIBIN to assist in solving crimes and apprehending suspects.