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Back to Archives | Back to December 2009 Contents 

Nab'em with NIBIN: Ballistics Imaging Technology

Tom Cramer, Writer-Editor, Liaison Division, Bureau of Alcohol, Tobacco, Firearms, and Explosives, Washington, D.C.

n a quiet Dade County Florida neighborhood, a man and his son are murdered while they sleep. Their home is ransacked and robbed. When Miami-Dade police arrive at the scene, the killer is gone, but the cartridge casings from his .22-caliber weapon are not. They lie on the floor near the victims, and police carefully collect each one, preserving valuable evidence in this case.

Forensic technicians at the Miami-Dade Police Crime Laboratory enter, or scan, the casings into an Integrated Ballistic Identification System known as IBIS, deployed by the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF). The system creates digital images of the casings, including the specific markings (microscopic scratches and dents) left on them by the shooter’s weapon. These markings are unique to that firearm and distinguish it from all other firearms.

Six months after the father and his son are murdered, a man is arrested as he attempts to rob an armored truck. The suspect is carrying several weapons, including a Ruger .22-caliber pistol.

Police test fire the Ruger and enter the cartridge casing into IBIS. The system correlates and compares this latest cartridge casing to the thousands already stored in its memory and quickly comes up with a “hit.” A hit, technically speaking, is a linking of two different crime investigations where no known connection previously existed.

This particular casing came from the same gun used to murder the father and son half a year earlier.

Along with this and other information collected during their investigation, police officers are able to build a strong case against the suspect. During subsequent interviews, he admits to his role in the two earlier homicides. An arrest is made, and the case is closed.

How It Works

Information is entered into IBIS in the form of digital images. These images are extreme close-ups of the scratches and other damage a bullet sustains as it leaves the barrel of a gun. Imperfections on the interior of every gun barrel are unique; these imperfections leave unique striations on each bullet traveling through the barrel.

Likewise, each cartridge casing becomes a one-of-a-kind individual the moment the trigger is pulled. Most often, the end of each casing sustains a distinct breech face and firing pin impression. In the case of autoloading pistols, each cartridge casing also picks up distinct ejector marks that are completely unique to the firing weapon.

Digital images are created from spent ammunition components found at a crime scene, or they can be created by test firing a crime gun into a shoot tank—essentially a big tank of water that slows the bullet, allowing it to sink undamaged to the bottom of the tank.

The images are then correlated (in a matter of hours) against thousands of earlier entries via electronic image comparison. If a high-confidence candidate for a match emerges, a firearms examiner compares it microscopically to the original evidence to confirm a match.

By searching in an automated environment locally, regionally, or nationally, system users are able to identify links between crimes more quickly, including cross-jurisdictional links that would never have been identified absent this technology. For example, authorities used the system while hunting for the shooters in the Washington, D.C., sniper case.

Staying Connected

ATF has made NIBIN available to law enforcement in every major metropolitan area. The grid that connects nationwide IBIS users is called the National Integrated Ballistic Information Network, or NIBIN. Currently there are 162 NIBIN partners (mostly state, county, and city law enforcement agencies or crime laboratories) in possession of IBIS systems at 199 locations. ATF administers the high-speed network over which the units communicate.

NIBIN’s ever-growing database now contains more than 1.5 million images of shell casings or bullets recovered from crime scenes, as well as casings or bullets from test fires of recovered firearms. This work has paid off with more than 28,000 confirmed hits by NIBIN partners. Each hit links at least two shooting incidents (56,000 cases linked) giving police the ability to combine and leverage information from each incident. More than 5,000 of these hits occurred in 2008 alone.

The New York City Police Department leads all partners in NIBIN hits with over 2,100. The Illinois State Police (Chicago) and the Allegheny County (Pennsylvania) Medical Examiners’ Office share second place with more than 1,500 hits. The Santa Ana (California) Police Department and Newark (New Jersey) Police Department share third place with over 1,000 hits.

Any law enforcement agency can gain valuable investigative information from the NIBIN system. Criminals today are very mobile, and evidence linking their shooting crimes can be sitting in the property rooms of different police agencies. Today, the successful solving of a murder in one jurisdiction depends on what police in other towns are doing with their ballistics evidence. While there are many towns not in possession of a NIBIN system, that does not preclude the jurisdiction from gaining access to it. To gain access to NIBIN many agencies have entered into agreements with existing NIBIN partners to enter their ballistic information on their behalf.

NIBIN partners can benefit most from the technology by entering all of their firearms evidence into the system, including crime scene evidence and test fires of recovered firearms. Entering crime scene evidence is especially important. Experience has shown that the higher the percentage of crime scene evidence entered on the network, the higher the hit rate.

Becoming a Partner

Of the existing 214 NIBIN-deployed IBIS systems, 201 are ATF-procured and ATF-funded for service/maintenance. Each IBIS system costs ATF about $230,000. The agency spends an additional $13 million annually on service and maintenance. In order for prospective partners to receive an ATF-procured IBIS deployment, they must sign a memorandum of understanding with the ATF in which they agree to do the following:

  • Enter all ballistic information from violent crime scenes

  • Enter as much ballistic information as possible from crime gun test fires

  • Possess a casing/bullet recovery system

  • Provide adequate personnel to operate the IBIS system (including a technical person on staff capable of performing forensic microscopic comparison of ballistic evidence)

  • Fund new user travel for a one-week ATF-funded training course

  • Share NIBIN investigative lead information and results with the ATF

Governance of NIBIN is by an executive board and a Users Congress. The NIBIN Executive Board, representing federal, state, and local law enforcement, makes recommendations and provides guidance to the ATF regarding NIBIN operations, rules, regulations, and procedures; ballistic imaging technology, standards, applications, and networking; software and hardware upgrades; and IBIS system deployments, moves, and removals. The NIBIN Users Congress is the technical working group of the NIBIN Executive Board. It consists of one primary and one alternate representing each of the 20 Users Congress regions. All of these representatives are experienced NIBIN users, and most are certified firearms examiners.

NIBIN Support System

ATF special agents are assigned as NIBIN regional coordinators (representing four regions across the United States) and as NIBIN field division coordinators (representing ATF’s 25 field divisions). In addition, ATF employs contractors nationwide as NIBIN firearms crime analysts. These three groups of ATF personnel support all NIBIN partners and participants from the field in an effort to ensure that NIBIN information and assistance is readily available to every existing or prospective NIBIN partner and participant.

ATF firearms examiners and IBIS specialists are assigned to each of ATF’s three forensic science laboratories located in Georgia, California, and Maryland. These three groups of ATF personnel support all NIBIN partners and participants by coordinating expert forensic training, support, and oversight.

Since 2006, the number of NIBIN entries has increased from 140,000 per year to over 200,000, and the number of hits has increased from 3,500 per year to over 5,000. Clearly, NIBIN partners are becoming increasingly more proficient with the technology.

Staying Out in Front

The local and state partners in the NIBIN system have worked to enhance the program through testing new technologies and developing best practices.

The Boston Police Department has been testing a new system that could replace the present bullet capture device (IBIS Bulletproof). The new system being tested is called BulletTrax – 3D (B3D). B3D went operational in late November 2008, and the technology appears promising. Other NIBIN partners such as the Santa Ana Police Department have sent evidence and personnel to the Boston Police Department in order to take advantage of the newer technology available in the B3D system. This system shows promise of having a higher success rate than the older system.

The Los Angeles Police Department developed a program called Walk-In Wednesdays where once a week detectives cut through much of the backlog of cases confronting their firearms section and bring high-priority cases right to a firearms expert. These cases receive priority going into the NIBIN system for testing. This program has been recommended to other agencies around the country as a best practice in solving firearms-related crime.

Become Part of the NIBIN Team

If your law enforcement agency is not already participating in NIBIN, please visit the Web site at, click the Points of Contact button, and contact your assigned NIBIN Regional Coordinator for participation assistance. Or simply call the NIBIN office at ATF National Headquarters in Washington, D.C. The number is 202-648-7140.

NIBIN has and will continue to prove its worth as a key tool in helping ATF and its law enforcement partners remove violent offenders from America’s streets.


• NIBIN entry of all spent ammunition from violent crime scenes and crime gun test fires (suitable for NIBIN entry)

• Investigation of all NIBIN-generated investigative leads and sharing of all cross-jurisdictional hit information (if applicable), in order to solve, reduce, and prevent firearms-related violent crime

• Recording and reporting to ATF all NIBIN-generated investigative and judicial results in order to demonstrate program success

How It Works: Every firearm has individual characteristics that are as unique to it as fingerprints are to human beings. When a gun is fired, it transfers these characteristics––in the form of microscopic striations and other imperfections––to the bullets and cartridge casings fired through it. The barrel of the gun marks the bullet traveling through it, and the weapon’s breech mechanism marks the ammunition’s cartridge casing.

Taking a Closer Look: IBIS systems allow NIBIN partners to enter digital images of the markings made on spent ammunition recovered from a crime scene or from spent ammunition from a crime gun test fire. The images are then correlated against a database of thousands of earlier entries via electronic image comparison. If a high-confidence candidate for a match emerges, the physical evidence is compared via microscope to confirm a match, or NIBIN “hit.”

Fire Away: A technician at the ATF National Laboratory fires a crime gun into a shoot tank (a big tank of water), which allows the bullet to be recovered, undamaged. The bullet and its casing are then entered into IBIS, which scans the 1.5 million such images already in its “brain” in search of a match, or hit.

Searching the Database: NIBIN’s evergrowing database now contains more than 1.5 million images of shell casings or bullets recovered from crime scenes, as well as casings or bullets from test fires of recovered firearms. ■



From The Police Chief, vol. LXXVI, no. 12, December 2009. Copyright held by the International Association of Chiefs of Police, 515 North Washington Street, Alexandria, VA 22314 USA.

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