Chattanooga Police Sgt. Josh May, the supervisor of the gun unit, speaks with visitors from several out-of-town law enforcement agencies about the gun unit and the implementation of NIBIN at the Chattanooga Police Services Center Thursday, March 28, 2019 in Chattanooga, Tennessee. May discussed a variety of topics during the event revolving around establishing a preventative gun violence strategy.

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Much like fingerprints, guns leave unique markings on casings.

Those markings help the Chattanooga Police Department's gun unit link guns to crimes, sometimes forming sprawling webs of incidents, revealing just how intertwined the city's gun crimes can be.

Last month, 15-year-old Ja'Mond Moorer was convicted of second-degree murder in the 2018 shooting death of 18-year-old Iziyah Spence. A ballistic match aided in that conviction by showing how a gun was linked to the evidence found at the scene.

It's just one of a growing list of cases that ballistic evidence has helped close.

Chattanooga's gun unit has been in place for a year now, and already it has become a nationally recognized model for how mid-sized cities can track — and hopefully reduce — gun violence, law enforcement experts say.

For gun unit supervisor Sgt. Josh May, working to stop the cycle of gun violence is more than just a job.

"You get tired of seeing dead bodies. You get tired of talking to kids who, at 10, 11 years old, know more people who are dead than you did, [more] people with bullets in them than you do. It's disheartening."



The gun unit was launched on June 1, 2018.

It was May's brainchild and was spurred by spates of violence, including one especially violent weekend in January 2017 that left two people dead and five others wounded.

Then-police Chief Fred Fletcher was already planning to ask for funding to add 14 new officers to the force. When he heard Josh's idea, he signed on and announced those officers would staff the gun unit and rapid response teams, which would follow up on shots-fired calls around the city.

The unit, Fletcher said, would use a system called the National Integrated Ballistic Information Network, or NIBIN, to help track and solve violent crimes.

NIBIN itself wasn't new to the department, though. Mayor Andy Berke had pushed for the purchase of the system a year earlier in 2016, saying it would allow police to quickly match — within hours — particular shell casings to specific guns, similar to the way police track fingerprints. It would replace having to send evidence to the Tennessee Bureau of Investigation's crime lab in Nashville, which had up to a 48-week turnaround, something that slowed investigations down.

What May envisioned was a team dedicated to using the system.

So in August 2017, he went to the city council with the plan. He told council members the police department could do more to fight crime by focusing on evidence gathered at scenes and using technology to track gun crimes.

"My vision [is] before we get to a homicide, utilize this technology, this manpower, on these shots fired to link this gun to this person to make quality cases," he told council members at the time.

The council approved the plan, and at $1.7 million, it was the single-largest personnel expense for the department that year.

A year later, the gun team has grown to 15 officers, and there are plans to add a NIBIN technician, a position funded by the Bureau of Alcohol, Tobacco, Firearms and Explosives.

Roughly 1,300 shots-fired calls are recorded in Chattanooga each year.

Of those, only about 20-25% actually have evidence of a gun being fired — things such as casings, bullet holes or witnesses. That's because people sometimes report cars backfiring, fireworks or anything else that could be mistaken for gunfire.

Before the gun unit was formed, those calls — the ones reporting a house being shot at, for example — fell into a sort of "grey zone," May said. There was an initial response to check the scene, yes; but because no one was injured, Major Crimes department investigators couldn't follow up. (Major Crimes deals with incidents that result in victims.)

"There needed to be somebody to come in and fill that void," May said.

Now, since the formation of the unit, each shots-fired call in Chattanooga gets at least an initial response, and if evidence is found, members of the gun team follow up within about 24 hours.

Already, there have been more than 432 shots-fired calls as of June. Of those, about 102 had evidence of gunfire.

And the system doesn't just benefit Chattanooga. At least 16 neighboring law enforcement agencies and jurisdictions — including the Hamilton County Sheriff's Office, Cleveland, Red Bank and East Ridge — have agreements with Chattanooga police and are able to access and input data, as well.

While the ultimate goal is to drive down violent crime, shots fired amount to much for the communities where they occur, May said. There are also emotional wounds.

"[It] causes so much PTSD for individuals It reverberates through an entire system, because these kids listen to [gunshots], they hear it, they see it, then they have to go to school. And they're expected to learn?"

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NIBIN is maintained by the ATF, the federal agency tasked with investigating and preventing the unlawful use of firearms and explosives, acts of arson and bombings, and illegal trafficking of alcohol and tobacco products.

It allows law enforcement agencies across the nation to compare their ballistic evidence.

Since its inception in the late 1990s, the database has collected more than 3 million pieces of evidence, the agency reported in 2018.

To get a match, technicians feed single shell casings into a machine that takes 3D images and loads them on a computer. Those images are then uploaded to the National Integrated Ballistic Information Network, and if a match is found investigators are notified. Specialists then have to manually confirm the match before it's considered official.

That information lets gun unit investigators know in what crimes the gun was used.

Another resource that the Chattanooga police's gun unit uses is the ATF's Electronic Tracing System, or eTrace, which can let police know who originally bought the gun. That gives police at least a starting point, because that person may know who they gave or sold the gun to, or when and where it was stolen, if they didn't already report it.

But where the eTrace system falls short is a lack of record-keeping by some retail gun dealers. Every time a dealership goes out of business, they have to send their records to ATF offices, and there's no regulation on how records should be kept. That creates a massive backlog for document examiners, who sometimes have to comb through handwritten index cards, tracing paper, or password-protected hard-drives, USA Today reported in late 2015.

May said the system helps them target those who are violating firearms laws, not responsible gun owners.

"There's this misnomer that we're trying to get all these guns off the streets, take everybody's guns, and that's not the case whatsoever," May said. "The vast majority of gun owners and gun possessors are extremely responsible individuals."



Ballistics and crime gun tracing still doesn't answer the million-dollar question: Who pulled the trigger?

NIBIN by itself can't lead to an arrest.

"It's not a magic machine like that," May said to a room full of people representing six North Carolina law enforcement agencies who were visiting Chattanooga in March to learn how the department organized its gun unit.

"You can't just put it in and all of a sudden all your crimes go to 0.0 [%]," he told them.

Investigators have to tap into other methods of intelligence gathering, ATF Assistant Special Agent in Charge Benjamin Gibbons said.

"[Ballistic information] in and of itself will not necessarily say this person did it," Gibbons said. "You have to use other investigative tools. That means interviews, video all those kinds of things."

That's where that follow-up comes in — the tracking of shootings and keeping an ear to the ground to stay on top of what the streets are saying. All of that together is helping police fine-tune their ability to track the violence and, in some cases, stop would-be shooters.

"If your mission is to start following up on NIBIN leads and shots fired, you have to keep that mission going," May told the visitors. "You have to, because the community deserves it."

Because NIBIN alone can't lead to an arrest, it's difficult to measure the success of the system alone. Non-fatal shootings or shootings without victims don't have a clearance rate — at least not in Chattanooga. (A case is identified as cleared when an arrest is made, the offender dies or if the death is determined to be justified, meaning there was no criminal intent.)

That's partly because suspects in non-fatal shootings or shootings without a victim may be charged with aggravated assault or reckless endangerment, meaning they're grouped with other types of crimes that aren't necessarily firearm-related.

Times Free Press records show that only seven of this year's 35 non-fatal shootings, excluding those deemed justified by police, have resulted in arrests. The newspaper does not keep data on shootings without victims.

But while numbers are quantifiable, they don't tell the whole story, May said.

Over time, crime is actually trending down, he said — a pattern that has been seen across the country for the past few decades.

And there's often a reason for spikes and drops in numbers. Sometimes it's because a main player is in jail, or a new group is on the rise because of that arrest. But those things are hard to legally prove, which is why police don't often release that information.

"Crime is such a roller coaster," he said. "We're always on the brink of utter chaos at times. You've got people out here who just don't get along, who have access to firearms, who have a complete disregard for others' lives and safety. So if that perfect storm rises you have [shooting] back and forth."

What has made NIBIN successful here locally is the coordination among the police department's various units, other local agencies and state and federal prosecutors, special Assistant U.S. Attorney Kevin Brown said.

While the state usually takes victim-driven cases — something that's probably going to require victim testimony, he said — federal prosecutors handle cases in which the victim is uncooperative or hasn't come forward.

"We meet about once a month [and] lay eyes on every gun arrest that's occurred in the preceding month," Brown said.

During those meetings, they discuss what kind of outcomes each case would have on the state and federal level to then determine what kind of plea deal to offer a defendant.

"The gun team and NIBIN is just another tool that I and other prosecutors in the U.S. Attorney's Office use to determine who need perhaps stiffer sentences," Brown said, "in an effort to reduce that violence, and ultimately, get a gun out of someone's hands and someone off the street before they do commit homicide or do commit a shooting."

So far, the coordination has proven useful in many cases.

Since 2017, Chattanooga police have made 3,338 NIBIN entries. And so far this year, the gun unit has identified 61 guns used in a crime.

It feels like Christmas every time a match comes back, May said.

It's one of the best parts of his day, he said, "because it gives us the opportunity to help someone who may have felt they weren't going to be helped."



Despite NIBIN's usefulness, though, it's only as good as the evidence put into it by investigators, according to experts.

A 2013 study by the National Institute of Justice noted the system had significant "untapped potential" because the implementation of NIBIN varies greatly across the country.

Researchers noted there was a large variation among sites in the amount of time it took to process ballistic evidence and identify matches.

"Long delays mean that once a [match] is sent from the crime lab to law enforcement, it might be too late to aid a particular investigation," the study reads.

Timeliness is important because the type of gun crimes that police are investigating today are repetitive and retaliatory in nature, said Pete Gagliardi, a retired ATF special agent in charge who consults with police departments on how they use forensic technology.

"The longer a shooter stays free, the more opportunity he or she has to shoot and harm again," he said.

Evidence needs to be processed in a timely manner to have a better chance of identifying the suspect and hopefully stopping any future shootings, Gagliardi said.

Since the study was released, ATF officials have created a list of standards for best practices. Among the agencies he says are doing it well is Chattanooga, Gagliardi said, adding it's an example of police leveraging the technology in a way that "allows them to do the comprehensive collection of crime gun intelligence" and in quick, efficient way.

He's even included the department in his latest book, "The 13 Critical Tasks: An Inside-Out Approach to Solving More Gun Crime," which accompanies each Integrated Ballistic Identification System purchase. IBIS is the machine by which evidence is entered into NIBIN.

The ATF also has recognized Chattanooga's gun unit framework as a model for best practice, as has the International Association of Chiefs of Police.

That recognition has caught the attention of several other agencies that, like those from North Carolina, have traveled to Chattanooga to learn from May.

But he doesn't take all of the credit.

" It's not successful without the men and women of the police department putting those ideas into play," May said, "because if they're not going to buy in and not going to do it, then where are we?"

He said he enjoys showing other agencies how to best use the technology.

"We're only going to be as successful as all the other agencies are," he said. "Because if they're not doing the same things, then what are we trying to accomplish?"

For May and his colleagues, the accomplishment would be stopping gun violence.

"You shouldn't be a 22-year-old rookie out here having to see multiple dead people in your shift," he said. "That's not natural. It's not good for anybody. There's a lot of baggage to be carried in one incident that people really don't know about. 'It's your job.' Yeah, it's my job. Doesn't make it any different."

Contact Rosana Hughes at or 423-757-6327 with tips or story ideas. Follow her on Twitter @HughesRosana.

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