Tag Archives: firearm identification

Firearms Analysis in New Orleans

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Firearm discharge

Cloud of particulates formed at firearm discharge to determine the distance a weapon was fired. Source: US Fish and Wildlife Service.

Last month, Bill Capo of New Orleans’ WWLTV posted a report on changes in that city’s police crime lab since Katrina. When Ronal Serpas assumed the position of crime lab superintendent, he found that the hurricane had destroyed the original lab, leaving a facility that barely functioned.

“This crime lab was basically dead on arrival,” Serpas told Bill Capo. “It was having very little success in doing firearms examinations. There was no real work going on with DNA.”

Serpas initiated a program to rebuild the lab with an emphasis on firearm identification to tackle the increasing number of violent crimes.

“It’s unbelievable the volume of work the firearms unit has done,” said Captain Michael Pfeiffer, the crime lab’s commander. “No place else in the country touches the volume of work this unit does. I can guarantee you, pound for pound, we are faster and better than anybody you want to look at.”

One outcome of the analysis is the finding that in many cases the same guns are used to commit multiple crimes. Investigators use the information to identify links between two or more crimes.

“There’s a small group of people out there committing a majority of the gun violence that occurs in the city of New Orleans,” Pfeiffer told Bill Capo, “and the more we can show the linkages between those people, and between the cases, the more likely we are to take, not just individuals, but groups off the street.”

If you plan to include forensic firearms analysis in your story, then watch the video of this report for insights into a real lab.

 

NIBIN

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Case comparison

Photo shows two test-fired cartridge cases from the same firearm compared side-by-side with a comparison microscope. Source: Stephen G. Bunch et al., “Is a Match Really a Match? A Primer on the Procedures and Validity of Firearm and Toolmark Identification,” Forensic Science Communications 11(3) (July 2009).

 

Fourteen years ago the ATF (today, called the Bureau of Alcohol, Tobacco, Firearms and Explosives) set up the National Integrated Ballistic Information Network (NIBIN). US partners of this network use Integrated Ballistic Identification Systems (IBIS) to obtain digital images of marks on fired cartridge cases and bullets. These cases and bullets are either recovered from a crime scene or from a test firing of a suspect weapon. The images are electronically compared with stored NIBIN entries. On TV shows, an electronic match – a hit – often ends the investigation. In real life, a high-confidence electronic match means that a firearms examiner compares original evidence with a microscope to confirm the match. So far, NIBIN partners have confirmed more than 50,000 NIBIN hits.

Last month, KVOA’s Lupita Murillo in Tucson reported a practical problem with NIBIN analysis. Although an electronic comparison may only require hours, somebody has to acquire and upload digital images into the network. The Tucson Police Crime Lab had 1,200 backlogged cases that needed to be entered into the system.

 

Forensic Firearms Identification

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Silver to bullets

Poster printed by Sir Joseph Causton & Sons, Ltd, London, 1915. Source: Library of Congress.

Forensic firearm examiners determine whether a certain weapon fired a bullet or cartridge found at a crime scene. Early efforts linked spent ammunition with a class of weapon. Following the 1862 shooting of Confederate General Stonewall Jackson, for example, investigators concluded that the General had been accidentally shot by his own side. The spherical projectile removed from the General had been fired from a smooth-bore musket, a type of weapon that the Union Army no longer used.

In 1912, Professor Victor Balthazard at the University of Paris formulated the basic principles of firearms examination. Using enlarged photographs, he compared marks created by a firearm on the surface of bullets and cartridge cases found at a crime scene with marks on ammunition that he had fired from a suspect weapon. In this way, he could connect crime scene ammunition to a particular firearm.

During the 1920s in New York, four men rediscovered Balthazard’s principles and initiated modern firearms identification: Charles E. Waite, Calvin Goddard, Philip O. Gravelle, and John E. Fisher. Gravelle had extensive experience with a comparison microscope to study fine details in cloth patterns. He suggested that they might be able to use the instrument to compare fired bullets and cases.

In a signal event of firearms identification, the group bought two comparison microscopes and modified them. They added a comparison bridge, and rotatable mounts for bullets and cartridge cases. Through the eyepiece of the bridge, two pieces of spent ammunition could be examined, one on each stage of the two microscopes.

Police departments and the courts became aware of the value of “fingerprinting” bullets, especially after Goddard testified about his findings in the 1929 St. Valentine’s Day Massacre. Within a decade, firearms identification became an established technique of criminal investigation.

Microstamping Could Yield Macro Benefits

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Example of microstamp placement

 

Traditional firearm identification is based upon the fact that every weapon has unique features introduced during manufacture and later caused by wear. These characteristics of a firearm create striated and impressed marks on fired ammunition that enable an examiner to identify a round of fired ammunition as coming from a particular gun. This analysis requires an examiner to have access to a suspect firearm that can be test fired to produce a bullet and cartridge case.

A method called microstamping could radically change firearm identification practice. Using lasers, unique alpha-numeric codes are added to certain parts of a firearm, such as the firing pin and breech face, and these identifiers are stamped onto a cartridge when fired. A code could reveal a firearm’s manufacturer, model, and serial number. The serial number alone would lead investigators to the identity of the person who first purchased the firearm.

Proponents of microstamping claim that the technique would not only aid a criminal investigation, but also would reduce the supply of illegal firearms. Microstamping, the argument goes, would deter people with clean records (straw buyers) from purchasing guns for criminals.

Since the technique was proposed, microstamping has generated controversy about the method’s reliability. A study posted on the New Yorkers Against Gun Violence website indicates that microstamping works.